I enjoy your videos, you remind me of a friend from years ago. A video on how to add the oil to the rec/dryer would be good or how to flush the components. There are lots of videos that say "add some oil to this or that but neglect to say how and how much. Keep up the good work on these old cars.
I gotta share my story: I am the original owner of a 1990 560SEL with about 125K miles. I brought the Benz into a nearby dealership (one of if not the biggest in NJ) and the same dealership of my original purchase but a different location. The AC wasn't working. They added coolant with color trace, and asked me to drive it a while. The AC worked for two months, and there was no sign of color. And then the statement from the mechanic that would haunt me for the next 3 years, "if there's no leak, then it must be the compressor." Replaced compressor --- a few $100s gone. Winter comes and goes, and 13 months after the repair, the AC stops. The exact same line, "no leak, new compressor." One month after warranty, a few more $100s. Now the AC lasts a matter of a week or two. The chief mechanic (yeah right) finally opens the dashboard, and voila --- dye color everywhere inside!!! "Wait a minute," I said, "If all this time it was a leak, then there was nothing wrong with my compressor, right?" The mechanic denied saying anything and still insisted it could have been the compressor. Now the repair was $1000. I could get no satisfaction there or at Benz HQ --- but about $4000 later, they did give me 2 free oil changes. Needless to say, I wouldn't have them do that.
Holy sweet Moses. That is quite the story. I am sorry to hear of this happening to you. Them using dye instead of using other ways to trace back the leak is a give away - the dye causes a variety of other unwanted consequences. I am puzzled that this service provider used that. Yikes that was a LOT of money you spent on that issue. Hoping you are having better luck nowadays.
I have been told by several mechanics that the molecules of R134 are smaller than Freon R12 and as such, the converted systems are susceptible to slow leaks over time, requiring annual " topping off". If the system gets low enough, the clutch will not engage - so check your R134 levels before replacing parts of the system.
Using the correct O rings is essential in successfully converting these older systems. I have not observed the need for annual topping off of such converted systems.
@@sas8403 R134 Orings are made from hydrogenated Nitrile and I recommend changing all of them. The black ones are typically made out of Buna and they tend to swell when exposed to the wrong Freon. It is a good time to install a new compressor, expansion valve, and dryer. Flush the system well and put a good vacuum on the system before filling it up with R134. Use the correct compressor oil (ester based) and your AC will run almost like with R12. At idle it will not perform as well but at speed you cannot tell the difference. Good luck.
The main problem with an old expansion valve is the o ring at the end cap that leak . You can buy a pump to empty the system in an approved container for little money .The pump is around $300 , the container $ 60 . This is what techs use on houses a/c . Will also do cars nicely . So, if you fill a system like 134a , then have an issue , empty it with the pump , fix the problem , put the gas back in . look on e bay , dozens of those pumps there .
Great video. i would add, if you convert a system from R12 don't put the same amount of R134a in the system. The red sticker says 1,3Kg but that is for R12. R134a system needs less. use only around 900g. i don't know the physical stuff behind this but if you use the same amount of r134a the pressure in the system is too high and can damage your system. i learned this the hard way. and i made the experience most workshops don't know this, even specialized AC shops. So if you bring your car to a workshop and just say" fill my AC up" they maybe look on the red sticker and fill 1,3kg in. you can also buy a sticker for r134a as an offical part from MB. it's green. i had this on my previous W126 and it was 2 Euros or so. Maybe i search for the part number later
@@straybenzes Hello, here is the part Number for the green R134a AC sticker: A 124 817 82 20 it's now about 5 Euros from Mercedes ...or 15 Euros on Ebay ;-) It says 1,0 kg R134a i would also suggest, check the water drains from the AC system. especally the driver side, because there is a hose made out of foam with a metal spring inside and if it's worn out your condenswater will leak into the interior. and it will be worn out because no way simple foam does last that long. often for a long time before you notice it because the carpets soak the water up. i noticed it this summer because i had no water puddle under my car while using AC. the hose is still available (A 126 830 11 96) but i would suggest search for a matching rubber hose from your homework depot because this foam hose is a pathetic faulty construction from MB.
@@vornamenachname5589 Very nice info. I have fixed a few with heat shrink tubing and also hose from a CPAP machine. The OEM can not be considered a hose - no idea what they were thinking.
A rat chewed through the cluster of small vacuum lines (on the passenger side that run alongside the battery and go in through the firewall) of our 1978 W123 300D. Prior to that the AC worked fine. I spliced the lines together again sort of OK but the AC won't work after that. Have you ever come across this problem?
oof. Yeah, I have seen plenty of rodent damage in the engine compartment. Did the rat also get into wiring? The only thing I know to do is what you have started doing: trace the lines and make sure that they are properly connected again.
@@straybenzes have you done a diesel purge before, and if so how do you keep (on a w123) fuel from pouring steadily out of the hard return line that attaches to the cigar hose going to the main filter? I need to also change the fuel prefilter but I can imagine the fuel is just going to pour out. Is there a way to stop that siphon action going on?
@@IshawooaPass Well, I am an old fashioned Diesel mechanic and have not attended the Diesel Purge church. Sorry for not having any advice to give to you.
I changed the air conditioner radiator, the compressor, and the pressure sensor installed in the tank, and cleaned the entire cooling cycle. It worked for ten minutes, then after that, the belt drive cycle became faster than the compressor clutch cycle. I began to suspect the condenser because it gets dirty during the rotation of the compressor. How do I check it?
Did you also clean the expansion valve or did you replace it? If you left that in place, did you flush the hoses going both ways, incessantly? If you did not than I highly recommend you do this. Change out the dryer and do not forget to put an ounce of compressor lubricant in it before closing the system up and putting a good vacuum on it for at least 30min.
@@straybenzes No, I did not clean the expansion valve or disassemble it, nor did I clean the inside of the refrigerator, but I did clean the hoses as well as the condenser and compressor. But I do not know how to remove the expansion valve in order to clean or replace it If I clean the expansion valve, will it work well or do I have to replace it? Please advise, thank you
Hi sir nice job . I have a w123 77 mercedes but my Compressor is not turning off everything else is good by the I don't have the servo that Controls the heat and cool I have it bypass.
Hi I am from Iraq and one of your followers, and I have benefited a lot from your videos I have a question.. Can I use R134 instead of R12 in the refrigeration system? You have all my appreciation and respectful
What would cause a weird odor inside the cabin when the heater is blowing? Almost like oil smell/ coolant smell. Car smells like raw gas outside when the car is started too.
That should be two separate issues. Your heater core may be bad. Sometime thought, it is a leak in the engine compartment or behind the first fire wall. Behind that site the aux coolant pump with connections to the heater core and mono valve. It only takes a little coolant to stink up the cabin. Gas leaks can happen near the EGA, the main fuel distributor, and any other fuel system component. Also common are leaks near the fuel pumps, filter, and accumulator.
It is well hidden near the steering column. You need to remove the under dashboard cover and the driver's side cover of the center transmission tunnel. You also need to remove the instrument cluster to be able to loosen the one support bracket. You will also need crow's foot wrenches as this thing is very hard to reach. Make sure you mount ALL threaded connections by hand to make sure you are not cross threaded. The best of luck to you.
HI l loved this video, but my problem on my w124 e420 facelift car is different. first start of the day a/c works as intended but throughout the day the a/c doesnt come on, a/c gas is full, kompressor works i ran a manual ground wire to trigger it to come on so it comes on when i trigger it, also the front electric fans dont come on, i have replaced the switches on the thermostat and thermostat itself. if its on a/c blows cold but only works in the morning, my car doesnt have the Klima module and i honestly am running out of ideas as to where else to look. if you can help me out that would be awesome, please keep posting videos they are very informative and use it alot :) thank you.
Where are you located? I am unfamiliar with a non CCU equipped car. What does the center console control panel look like? Is this the dual zone unit? Anyway, what is the low pressure side at idle and 2000rpm in the afternoon? Is the compressor running at all?
I jumped the low gas pressure switch but still didnt get the compressor to run. I got the compressor running by jumping the wires on the ac relay connector. Can the reason be anything else than the relay?
It is most likely that relay. Make sure fuse 5 is intact though. The idle speed control unit can also cause issues if the high coolant temp switch senses temp above 110C or that switch is stuck closed. Good luck.
Excellent info, as always ;-). My '86 W126 hasn't been converted and is now out of storage after a 4-year hiatus. The A/C didn't blow very cold when it went into the garage, and (luckily?) I haven't tested it yet. Most interesting part to me is that you'd recommend converting the system to 134. Unless, perhaps, you have or would want to do a video on the topic, please help me understand why the conversion is advisable. I know R12 is very expensive now, and I have but one can to my name. (Not sure how many it takes). Another question I have is what the right sequence of events I should use to assess the operation of my A/C, considering you mentioned that running it with little or no refrigerant can damage the compressor. So, I'm afraid to even turn it on at the moment, for fear of damaging things. Maybe best to go straight to conversion? I wouldn't attempt the conversion myself, and wonder if Benz dealers even do it. (So, lots of room for more videos on these associated topics). Thanks again Ralf!
Hi Vic. I feel your pain. Here is my 2 Cents on converting to R134A from R12. Before you do anything ask around for local car shops to recover your R12 in your system. Near where I live in NE US I could not find a shop that would do that anymore. Then shops are very picky about evacuating old refrigerant that has any dye in it. They do not want that stuff in their expensive tooling. It is not only illegal to just vent Freon to atmosphere it is also very nasty. So before you do anything I would check out if your systems needs topping off old R12 which you could do with your one can. That assumes that your system is still holding pressure. Connect your AC gauge and see what the system pressure is even without the compressor running. If you still have 20-30PSI after four years it may be worth "just" recharging your system. That is where the mind game is starting as if you lose Freon you will also have lost compressor oil. A charged system is almost all but impossible to fill with oil unless you have special tooling for doing this. If the car is a beater it is not worth changing over to R134. Convert it if you have a nice car and you want to keep driving it without having to break a sweat in the summer (also, gas engine models had a fuel cooler that was using the AC evaporator return line to the compressor - it prevents fuel vapor lock). This is where you can spend a bit of money and you may be able to save a little here or there depending on how handy you are. Key to successfully enjoying cold AC even at engine idle is a compressor that is in top condition. If your compressor is only a few years old with very low miles/ hours on it you should be ok just replacing the O rings. For what exchange compressors cost to me it is worth just going with that and saving a lot of worries later. Plus, new compressors are typically already ready to run with R134 and are filled with Ester based oils. Then you need to pay attention to changing all the O-rings (the ones to use will be green in color). Flush the system one component after the other while you change the O rings. The most difficult component to get to is the expansion valve under the dash as per my video. Depending on who owned and serviced your car for or before you there can be copious amounts of debris in the system. This is especially true if lets say a compressor had failed before. I have seen a lot of junk come out of AC components and the expansion valve is very often plugged up with it - one of the key reasons even a fully charged system my not blow cold air anymore. Use dry shop air to blow out the special solvent and then you can start re-assembling the system. Install the new dryer last and put around 1-2 ounces of new compressor oil into it before you seal everything up. Do not forget to install a conversion low and high pressure adapter fittings (car parts shops have them). Now rent yourself a high vacuum pump and pump down the system to full vacuum. In the first couple of minutes shut down the pump and see what your vacuum gauge does. The needle must not move. Otherwise you have a leak somewhere. I usually keep the pump running for at least half an hour. This makes sure you boil all the moisture out of the system. That is a really crucial step quite a few folks overlook and moisture in your system will diminish your AC's capacity to cool. Charge the system with regular R134 and place a sticker (provided with the conversion fittings) near the car build tag so techs working on your classic Benz will be able to more easily work on your car. If you are not comfortable working on this system you can indeed ask your local Benz shop. You can also deploy FB and ask in the W126 group for recommended Benz AC shops in your area. Successfully converted cars are easier and cheaper to maintain, are environmentally friendlier, and the cooling capacity is almost up to par (the cars I converted would blow cool air even in 100F stop and go traffic). While the car in modest traffic and highway speed you will not be able to tell the difference. I am hoping this will help you. Good luck!
Next thing to check is the clutch itself. Look for the single blue wire going to the compressor clutch and connect it to plus. It should engage. If it does the next most probalbe cause for not working can be the Klima really. Change it out with a working one if you can. If that does not work then this may be due to a mulfunctioning ACC automatic climate control unit. Good luck!
So the compressor clutch does engage with the AC on? If so, then you "just" do not have enough of a charge in the system. If the clutch does not engage put a wire jumper on the low pressure switch on the AC dryer. If the clutch engages then you had a leak and do not have enough gas in the system. You can opt to just recharge the system, but I will caution you that when gas escaped it will likely do that again. And when gas escapes then oil does escape with it. If your system is totally empty I would check an top off the oil in the compressor. Many compressors get damaged from running without oil. Put a good vacuum on your system before recharging. Good luck.
I am not totally sure what you are asking. This fan is the single fan of the older W126. Later models had two fans. The W126 fan(s) will not fit on W124. Good luck.
I have a 1989 190e and the aux fans do not turn on. I have put 12v through the fans the switch and they all work. I have replaced the relays as well and still nothing. I need to fix this now because the summer heats are hereee!
Start the car and put the AC on max. Put a jumper wire on the high coolant temp switch. If they turn on then there is nothing wrong with them not being on. The main fan provides enough cooling air until the coolant temp gets too high.
@@straybenzes I am very sad, my dear friend, and lately I have been unable to sleep because I have the same problem and I do not know how to switch between untying and tying. I ask you to quickly make a video so that we can learn from you and solve the problem Please help me, my dear friend
@@kalfoogaltmimi5043 I need to see if and how much footage I have of this work. I cannot promise that I will have anything and It may take a little while before I have another on coming in for this repair.
Hi i just replace my compressor, condensor, dryer, thermostat at my local AC shop. But the ac only produce cold air at 21c with blower speed 1. I read the manual it should be 1-8c with outside temp 20-40c. and weather here is 32c average. What should i do next?
That is a loaded question. Is your system running R12 or R134A? Assuming it was converted to the latter, you can expect the AC vent temp to be in the 20C range with >30C outside temp - at idle RPM. While driving the AC vent temp should be closer to 10C. The AC compressor suction side pressure should be around 45psig with the AC on max and with the engine at 1500rpm. Was the expansion valve also replaced by your shop? It should have been replaced during a R134A conversion. Its tiny orifice can block up with system debris and only replacement or rigorous flushing can alleviate this issue.
@@straybenzes sorry my bad, i forget to mention my car type. mine is 1995 G300 (M103 engine) its already r134a since brand new. My local AC shop did not change the expansion valve. and i expecting the expansion valve already 20 years old. my system has no leak, pass the vacuum test. but i already ask another pro Mercedes AC mechanic since 1998, and he said the nozzle on the expansion valve might be worn out. so he recomend me to change it, and i will D.I.Y the job. do you have any advice for me? Thanks alot for the answer :)
@@mkwiipro5912 Well, do you have a Freon recovery system? Getting to the expansion valve and having the crow's feet wrenches is the biggest challenge. You will need to remove the instrument cluster, the center left console covering, and most likely a brace or two off the steering column. Good luck!
@@straybenzes in Indonesia (where i live) we are allow to throw away the freon to the atmosphere. And i will recharge my freon again with the same r134a. its only cost $30 for 1kg refrigerant (the amount of refrigerant, following the instructions for this car type) and this is my 3rd time to completely opening the dashboard, so i hope it will be an easy job for me. And i also have a vacuum machine, since i also fixing a few AC system in my house. Thx for sharing, i will contact you soon again when i need help. See you!
I used this stuff: shop.advanceautoparts.com/p/interdynamics-certified-a-c-pro-power-clean-flush-1.06-lbs.-ca-compliant-ca-1/7010021-P?searchTerm=a/c%20flushes%20&%20solvents . R134 works pretty well in the last two that I retrofitted this way.
Assuming that you pumped the system down to a good vacuum, charged the system with the correct amount of refrigerant, and there are no leaks then a possible culprit could be the expansion valve or the evaporator. Do you have an AC hose / gauge kit? If so, what is the low and high pressure before and after your compressor? A faulty expansion valve and / or evaporator will mess with those values and you can pretty much isolate the trouble.
I need your help.my w126 ac is working fine on low rmp speeds.but when hitting gas pedal the air flow getting very slow you can hear the ac as it is choked.
Hmm. I need a little clarification about what you wrote. When you say that the air flow is getting slow is that referring to the cabin air blower? Also, can you please describe what you are seeing, hearing, or measuring when you say that the AC is choked.
Yes the cabin air flow getting low vs acceleration .and when this happens I can hear the blower as it is circulation inside the dashboard but no air is coming out of vents.
@@Mohamed61110 That actually is related to either the climate control unit, the cabin air temp sensor blower, the blower motor, or the blower motor resistor. I would start with taking out the main blower motor and inspect the rotor and brushes.
Just FYI I noticed when this subject Start the economy guage started to stay on middle while normally it should stay on zero if car is on idle.i was guessing it might be some vaccume leal.
@@Mohamed61110 That should be an unrelated issue, but it is another issue that will need your full attention. If it is a vacuum leak close to the engine it should run idle and run rough. It could also be a leak closer to the instrument cluster.
That is a loaded question. If you have never worked on cars and / or AC systems I would recommend not messing with this system yourself. First step would be to measure the pressure on your system. Has it been converted to R134A yet? If so, then you can measure the pressure using a commercially available R134A refill kit. Connect it to the low pressure side of the AC system. Here it gets to be tricky. If you still have pressure, but just not enough to satisfy the low system pressure switch setting then you may be able to "just" recharge your system. If there is no pressure left I would stop right there because of two reasons: You will need to find the part that caused the leak. The second reason is that when you lose gas you also lose compressor lubricant. So "just" recharging the system may get it to work again, but you typically will run the compressor dry causing it's catastrophic failure. All that debris can also go into you evaporator and expansion valve. The latter is REALLY labor intensive to replace (you also need calibrated Swiss Army knife fingers to get there). Your call!
@@alanOHALAN You can only add oil with the system completely and properly emptied of Freon. You have to disconnect the compressor intake line in order to add oil. This is not a job for novices. What do you mean by heater valve? The mono valve?
@@alanOHALAN There are a few videos about the mono valve and how to fix it. In short I would get a cheap replacement valve and just use the rubber part. Replacing it on your old one (hopefully it is still the OEM part with the correct spring in it) is your best and perhaps only choice as OEM parts are no longer made.
Hi Ralph just curious when you remove the evaporator/expansion valve from the W126 with manual knobs did you remove the entire dashboard or is it accessible from below? Thanks!
You will need to remove the instrument cluster, carpet runner, center console side paneling on the driver side (LH drive), and the under dash cover. Then you need to loosen the black support bracket bolted to the steering column. In order for the bracket to move more freely you will also need to loosen the black wire zip ties. It is a pain to get to and super tight. Without removing this support bracket you will not get the crow foot wrenches to fit. Tighten every fitting by hand - the four expansion valve threads cross thread easily. You also will need a little extra foam as the foam wrapped around the expansion valve will likely just crumble on you. Good luck!
Stray Benzes Good Afternoon, I have a 91 300 SEL. I’ve put dye and sealant in the system three years in a row along with a full charge of Freon and there’s no visible signs of leaks with the UV light under the hood. The cold AC will last the entire summer. After watching this video I have a feeling it’s the expansion valve...what else can it be? 🤔 I had an issue today after putting a full charge of freon..... The AC system was blowing cold air yesterday and this morning I was getting no air or cold air out of the vents. The compressor and blower do work....ran direct power. After watching your video I feel like I should replace the drier, the ac pressure switch and sensor (the red one with wires and the one with a bolt & to male connecting ends). I had my friend remove all the Freon from the system. The only part that I’m concerned with is replacing the expansion valve...... I have a feeling that many places would know how to do it.
@@4423Scott You definitely have a leak in your system as you should not have to top it off every year. Is your system running on R134? If so, were all O-rings replaced during the conversion process? If not, that is where I would start. Also, remember that if you lose gas you also lose oil in the process and you run the risk of locking up your compressor. Many folks just switch over to the new gas type and overlook the condition of the compressor. Swap it out if it is older than 5 years and use Ester based oil with R134, The expansion valve and evaporator inside the cabin can definitely be the culprit of losing your charge. I would take the UV tool and inspect that area. If you used dye I would imagine you would see that leaving residue in that area as well. I will put an excellent tutorial on the removal of the expansion valve in the description of the video.
Hi Ralph! Awesome videos!!! I just got a 88 420SEL and it was told to the previous owner that the problem was the condenser. How can I test the condenser? I already unmounted, but saw your video of yours after I ordered from PatsGeek! And wanted to shoot myself. And yes they sent me the wrong one too. Sending it back it is more expensive than the buying price, so I used it for target practice!
Oh no! That was unfortunate. The only way that a condenser would be a problem would be if it was plugged. If you use compressed air on you old one and air comes out unobstructed than it was not the condenser. If you have the system apart you might as well flush the system one component at the time - don't leave everything connected and then use only the two hose ends to do a flush. The biggest pain is getting to the evaporator and expansion valve. Make sure to check up on compressor oil - yeah, another pain in the romp to do that. Install a new dryer too; those are cheap. Fill that one with a little less than an ounce before closing the system. Putting a solid vacuum on you system to make sure you get all moisture out and that there is no leak is really important before charging the system. If your system still gives you trouble you can use the high / low pressure gauge kit to figure out which side is not working correctly. You would have to recover the Freon again though before you can work on it again. Good luck!
I forgot...Same 1985 201 190D 2.2 ..it is pumping cold air thru the center and warm air on the side vents. Blend Door issues maybe? for side blow of warm air? Totally confused? All of the climate control switches and buttons all seem to operate CORRECTLY. Totally confused where to look at now?
To me this sounds like an issue I have read about here: www.peachparts.com/shopforum/tech-help/301897-1992-190e-2-6-why-warm-air-coming-out-sidevents-when-c.html
I have a 1988 560 SEL. My A/C clutch engages on a cold start for 30-60 secs then disengages. I just put more R134 refrigerant and I'm at 45 psi on the A/C Recharge gauge so I know it's pressurized now. My clutch still won't engage but everything else seems ok. Like the Auxilary fan works, I hear different clicks and sounds when I switch from A/C mode to Hot air on the climate but I cannot figure out why my clutch will not engage even though it starts ok. Does anyone know what the problem could be?
Do you have an AC hose / gauge kit or just the low pressure fill hose and gauge that comes with new refrigerant cans? If your system was charged and you had to top the system off that is already not a great sign. Based on the info you have provided there are still quite a few problem possibilities. It would be best connecting an AC hose / gauge kit. This way you can monitor the high and low pressure side of the AC circuit. Even if you only have the fill gauge off the AC freon can it can already be enough to literally see what the problem may be. With the AC set to max and the temp wheel set to max cool take a reading of you low pressure circuit. Watch what happens when the compressor kicks in briefly as you described. If the pressure goes down and the clutch disengages there is likely still not enough refrigerant in your system. It would be great if you also got a reading from the high pressure side. If the high pressure side rises in pressure and the low side keeps dropping pressure the expansion valves or worse the evaporator may be blocked. If you have to fill more Freon into your system please mind you that you may be running low on compressor oil also. Losing gas also means losing oil - you can lock up a compressor and if you are lucky before you burn clutch and CCU. Another quick test you can do is jumping the low pressure AC gas switch S31 at the dryer. Take a set of alligator clips and jumper the two wires. The compressor clutch should be engaging. Do not test this for too long - you may ruin the compressor. Good luck finding the gremlins!
Stray Benzes My guess was that there is a leak somewhere. The issue is that I inherited this car from my grandmother after she passed last year and I think the last time the A/C was touched was when it was converted to support R134 in the 90's. So when I recharged it the low pressure was at 0. So it seemed like there was no refrigerant left. Now it's at 45 PSI. All I used was the recharge because I thought adding some pressure would jump start the clutch again because of the sensor but it didn't work. The clutch only comes on when the engine is cold only for 30-60 seconds. Not sure why. I definitely need to get a compression kit. I just don't want to buy a new cmpressor because it actually seems fine. It seems like there is an electrical issue or something. Or it needs a new clutch. How do I add the oil in? Do I add it to the low pressure line?
@@quiltingrox Good news is that you have the history of the car. That info in worth gold. With that said I would get the system leak checked and then get the system evacuated again. If the car has sat around and the AC system has been without pressure for a while you should pull off the compressor and drain what little oil may be left. Flush the system component by component and then dry it out with either N2 or super dry shop air if you can. Use new R134 Orings throughout and then install a new dryer. Make sure to fill compressor with enough oil and put an ounce into the dryer. Pump down the system with full vacuum (I did forget asking you if you did this prior to filling freon into the system) for at least half an hour. You should do a leak test with vacuum before filling the system with new freon gas. It may be a good idea letting a shop you trust do this work.
Stray Benzes ok thank you for your help! What I do know is that the leak is super slow and small because it holds pressure very well. I have to think that there was a leak since the 90's and it finally drained out this year. How do I add A/C oil?
When did this start happening? For how long have you had this car? Is this happening with a cold or warmed up engine? Is it running in low or high speed? This could be the high coolant temp switch or the Klima relay. If it only happens with a hot engine it cold also be because the coolant is indeed that hot that the high temp switch engages.
Hello Ralf just an update and a detailed description of the problem with the old girl I have it since 2010. It is a 300SE 1990. The problem started one morning when I simply went out to start it turn the ignition on and before i cranked I heard the aux fan come on the engine was cold yes... This is strange right.. So I went out to see what was happening and noticed only one of the two fans were working theres another problem probably motor worn.. it is not fuse a fuse is changed and new but there suppose to both work in harmony and kick on together as the wires parallel. so my guess is its the motor on fan that's shot. A little test I done was on the CTS I disconnected it with ignition off then on. and it came on but just the one fan that only happen when car was cold too if warm that test doesn't work. I would higily appreciate you doing a video on the aux fans mine is a 1990 model so it has the upgraded dual fan set up but It looks like a PITA to remove with them plastic pop rivets on the shorund and access looks teribble to take the whole unit off the change the fan. Now I guess I have to say that il be honest that my A/C has been neglected as I havent converted it over to R134a only thing I done to it in regards to A/C was change the blower motor as the brushes were wore and it started squealing. I wasn't able to get a direct replacement though as there NLA. Other thing is I didn't know theres a modification you can make to the CTS to make them cut in at a lower temp. May look into this when I consider taking on the aux fan removel.
@@ZaneTravel233 Looks like you have two separate issues. One fan seems to be defective. Both are indeed wired in parallel and should run together. The other issue is that they are operating right from turning the car on. With AC on they are supposed to do that, but only in low speed.and with the high freon system pressure switch engaged. The high speed fan setting is controlled by the CCU that triggers based on the engine coolant temp sensor. Is your fan spinning at high or low speed? Fuse 5 is the main fuse for the high low fan speed relays K9 K10 and both of those get control voltage connected to air injection relay K17 (not controlled by it though). All of them sit in the main fuse box. I would check what the fan speed is next. Good luck!
Most confusing issue: 1985 W201, Diesel 2.2. Made a TOTAL and complete removal and replacment of every single hose, pipe, tube, , compressor, condenser, pressure switches , drier, expansion valve ...converted to R134 even electrical connectors for the fans . EVERYTHING. NOTHING of the old system remains. PROBLEM, The high side reads low pressure and the low side reads High pressure. Its like the compressor is running the opposite direction. ???? R134 was installed by weight as it should be..?????
Interesting. Why did all of those components have to be replaced? I usually only fix what needs fixing and usually only replace the rubber parts and expansion valve. Assuming you did everything correctly I would say let's start with the pressure values you are reading on your gauge assembly. What is the system pressure without the engine running? With AC on Max and engine running what are the pressure values on the high and low side ports?
@@straybenzes hi, so on my 300 td wagon I changed out the filter drier, expansion valve and compressor, the compressor clutch wont engage I also checked fuses, maybe a relay problem?
@@Decimusblack88 Try jumping the min pressure switch mounted to the side of the dryer and jumper the contact with the AC on and on min temp. If the clutch does not engage it can be the air conditioning relay and / or the ETR switch. Good luck!
Thank you for sharing. I bought a 93 190e last week that had been sitting for years and was able to get the air running again. Great video!🎉
That's so cool! Great job!
Hi, I just acquired an '84 300D. I have been watching other's videos, but must say your's are the best. You seem such a great guy. Thanks.
Thank you. Good luck and plenty of fun with your 300D. Great car!
Excellent and Awesome video!
Thanks!
I enjoy your videos, you remind me of a friend from years ago. A video on how to add the oil to the rec/dryer would be good or how to flush the components. There are lots of videos that say "add some oil to this or that but neglect to say how and how much. Keep up the good work on these old cars.
Thanks for the tips and feedback!
Thank you very much.
Can you do exactly on 260e M 103
Other than the engine and belt drive, the AC systems are identical among the different models. Which system conmponent do you feel is different?
Excellent video Ralph! Makes me wonder how many components I'm going to have to tend to get my '84 300D turbo AC back to cooling. haha lol
Keeping my fingers crossed for you.
I gotta share my story: I am the original owner of a 1990 560SEL with about 125K miles. I brought the Benz into a nearby dealership (one of if not the biggest in NJ) and the same dealership of my original purchase but a different location. The AC wasn't working. They added coolant with color trace, and asked me to drive it a while. The AC worked for two months, and there was no sign of color. And then the statement from the mechanic that would haunt me for the next 3 years, "if there's no leak, then it must be the compressor." Replaced compressor --- a few $100s gone. Winter comes and goes, and 13 months after the repair, the AC stops. The exact same line, "no leak, new compressor." One month after warranty, a few more $100s. Now the AC lasts a matter of a week or two. The chief mechanic (yeah right) finally opens the dashboard, and voila --- dye color everywhere inside!!! "Wait a minute," I said, "If all this time it was a leak, then there was nothing wrong with my compressor, right?" The mechanic denied saying anything and still insisted it could have been the compressor. Now the repair was $1000. I could get no satisfaction there or at Benz HQ --- but about $4000 later, they did give me 2 free oil changes. Needless to say, I wouldn't have them do that.
Holy sweet Moses. That is quite the story. I am sorry to hear of this happening to you. Them using dye instead of using other ways to trace back the leak is a give away - the dye causes a variety of other unwanted consequences. I am puzzled that this service provider used that. Yikes that was a LOT of money you spent on that issue. Hoping you are having better luck nowadays.
I have been told by several mechanics that the molecules of R134 are smaller than Freon R12 and as such, the converted systems are susceptible to slow leaks over time, requiring annual " topping off". If the system gets low enough, the clutch will not engage - so check your R134 levels before replacing parts of the system.
Using the correct O rings is essential in successfully converting these older systems. I have not observed the need for annual topping off of such converted systems.
so do all the o rings need replacing and are there specific o rings for r134
@@straybenzes
@@sas8403 R134 Orings are made from hydrogenated Nitrile and I recommend changing all of them. The black ones are typically made out of Buna and they tend to swell when exposed to the wrong Freon. It is a good time to install a new compressor, expansion valve, and dryer. Flush the system well and put a good vacuum on the system before filling it up with R134. Use the correct compressor oil (ester based) and your AC will run almost like with R12. At idle it will not perform as well but at speed you cannot tell the difference. Good luck.
The main problem with an old expansion valve is the o ring at the end cap that leak . You can buy a pump to empty the system in an approved container for little money .The pump is around $300 , the container $ 60 . This is what techs use on houses a/c . Will also do cars nicely . So, if you fill a system like 134a , then have an issue , empty it with the pump , fix the problem , put the gas back in . look on e bay , dozens of those pumps there .
Yup. I just have not seen a evac system for such a low price yet that is worth buying.
Great video. i would add, if you convert a system from R12 don't put the same amount of R134a in the system. The red sticker says 1,3Kg but that is for R12. R134a system needs less. use only around 900g. i don't know the physical stuff behind this but if you use the same amount of r134a the pressure in the system is too high and can damage your system. i learned this the hard way. and i made the experience most workshops don't know this, even specialized AC shops. So if you bring your car to a workshop and just say" fill my AC up" they maybe look on the red sticker and fill 1,3kg in. you can also buy a sticker for r134a as an offical part from MB. it's green. i had this on my previous W126 and it was 2 Euros or so.
Maybe i search for the part number later
Good point. It does indeed not take quite as much R134. Thank you for your thoughtful note.
@@straybenzes Hello, here is the part Number for the green R134a AC sticker: A 124 817 82 20 it's now about 5 Euros from Mercedes ...or 15 Euros on Ebay ;-) It says 1,0 kg R134a
i would also suggest, check the water drains from the AC system. especally the driver side, because there is a hose made out of foam with a metal spring inside and if it's worn out your condenswater will leak into the interior. and it will be worn out because no way simple foam does last that long. often for a long time before you notice it because the carpets soak the water up. i noticed it this summer because i had no water puddle under my car while using AC.
the hose is still available (A 126 830 11 96) but i would suggest search for a matching rubber hose from your homework depot because this foam hose is a pathetic faulty construction from MB.
@@vornamenachname5589 Very nice info. I have fixed a few with heat shrink tubing and also hose from a CPAP machine. The OEM can not be considered a hose - no idea what they were thinking.
A rat chewed through the cluster of small vacuum lines (on the passenger side that run alongside the battery and go in through the firewall) of our 1978 W123 300D. Prior to that the AC worked fine. I spliced the lines together again sort of OK but the AC won't work after that. Have you ever come across this problem?
oof. Yeah, I have seen plenty of rodent damage in the engine compartment. Did the rat also get into wiring? The only thing I know to do is what you have started doing: trace the lines and make sure that they are properly connected again.
@@straybenzes Thank you. I'll just have to see if I missed a chew hole somewhere and check all the wiring too
@@straybenzes have you done a diesel purge before, and if so how do you keep (on a w123) fuel from pouring steadily out of the hard return line that attaches to the cigar hose going to the main filter? I need to also change the fuel prefilter but I can imagine the fuel is just going to pour out. Is there a way to stop that siphon action going on?
@@IshawooaPass Well, I am an old fashioned Diesel mechanic and have not attended the Diesel Purge church. Sorry for not having any advice to give to you.
@@IshawooaPass The best of luck to you!
I changed the air conditioner radiator, the compressor, and the pressure sensor installed in the tank, and cleaned the entire cooling cycle. It worked for ten minutes, then after that, the belt drive cycle became faster than the compressor clutch cycle. I began to suspect the condenser because it gets dirty during the rotation of the compressor.
How do I check it?
Did you also clean the expansion valve or did you replace it? If you left that in place, did you flush the hoses going both ways, incessantly? If you did not than I highly recommend you do this. Change out the dryer and do not forget to put an ounce of compressor lubricant in it before closing the system up and putting a good vacuum on it for at least 30min.
@@straybenzes No, I did not clean the expansion valve or disassemble it, nor did I clean the inside of the refrigerator, but I did clean the hoses as well as the condenser and compressor.
But I do not know how to remove the expansion valve in order to clean or replace it
If I clean the expansion valve, will it work well or do I have to replace it?
Please advise, thank you
@@kalfoogaltmimi5043 The expansion valve has very small orifices that can can easily plug up with debris. You may have to get back into your system.
Hi sir nice job . I have a w123 77 mercedes but my Compressor is not turning off everything else is good by the I don't have the servo that Controls the heat and cool I have it bypass.
This sounds like your climate control system is in need of checking.
Hi
I am from Iraq and one of your followers, and I have benefited a lot from your videos
I have a question.. Can I use R134 instead of R12 in the refrigeration system?
You have all my appreciation and respectful
Glad you like it! Good luck.
What would cause a weird odor inside the cabin when the heater is blowing? Almost like oil smell/ coolant smell. Car smells like raw gas outside when the car is started too.
That should be two separate issues. Your heater core may be bad. Sometime thought, it is a leak in the engine compartment or behind the first fire wall. Behind that site the aux coolant pump with connections to the heater core and mono valve. It only takes a little coolant to stink up the cabin.
Gas leaks can happen near the EGA, the main fuel distributor, and any other fuel system component. Also common are leaks near the fuel pumps, filter, and accumulator.
@@straybenzes thanks.
@@wolfofms6898 😁
Where is the expansion valve located on a 1987 300sdl. Just replaced condenser, pressure checked, vac'd and charged and I still don't have cold air.
It is well hidden near the steering column. You need to remove the under dashboard cover and the driver's side cover of the center transmission tunnel. You also need to remove the instrument cluster to be able to loosen the one support bracket. You will also need crow's foot wrenches as this thing is very hard to reach. Make sure you mount ALL threaded connections by hand to make sure you are not cross threaded. The best of luck to you.
HI l loved this video, but my problem on my w124 e420 facelift car is different. first start of the day a/c works as intended but throughout the day the a/c doesnt come on, a/c gas is full, kompressor works i ran a manual ground wire to trigger it to come on so it comes on when i trigger it, also the front electric fans dont come on, i have replaced the switches on the thermostat and thermostat itself. if its on a/c blows cold but only works in the morning, my car doesnt have the Klima module and i honestly am running out of ideas as to where else to look. if you can help me out that would be awesome, please keep posting videos they are very informative and use it alot :) thank you.
Where are you located? I am unfamiliar with a non CCU equipped car. What does the center console control panel look like? Is this the dual zone unit?
Anyway, what is the low pressure side at idle and 2000rpm in the afternoon? Is the compressor running at all?
I jumped the low gas pressure switch but still didnt get the compressor to run.
I got the compressor running by jumping the wires on the ac relay connector. Can the reason be anything else than the relay?
It is most likely that relay. Make sure fuse 5 is intact though. The idle speed control unit can also cause issues if the high coolant temp switch senses temp above 110C or that switch is stuck closed. Good luck.
Excellent info, as always ;-). My '86 W126 hasn't been converted and is now out of storage after a 4-year hiatus. The A/C didn't blow very cold when it went into the garage, and (luckily?) I haven't tested it yet. Most interesting part to me is that you'd recommend converting the system to 134. Unless, perhaps, you have or would want to do a video on the topic, please help me understand why the conversion is advisable. I know R12 is very expensive now, and I have but one can to my name. (Not sure how many it takes).
Another question I have is what the right sequence of events I should use to assess the operation of my A/C, considering you mentioned that running it with little or no refrigerant can damage the compressor. So, I'm afraid to even turn it on at the moment, for fear of damaging things. Maybe best to go straight to conversion? I wouldn't attempt the conversion myself, and wonder if Benz dealers even do it. (So, lots of room for more videos on these associated topics). Thanks again Ralf!
Hi Vic. I feel your pain. Here is my 2 Cents on converting to R134A from R12. Before you do anything ask around for local car shops to recover your R12 in your system. Near where I live in NE US I could not find a shop that would do that anymore. Then shops are very picky about evacuating old refrigerant that has any dye in it. They do not want that stuff in their expensive tooling. It is not only illegal to just vent Freon to atmosphere it is also very nasty. So before you do anything I would check out if your systems needs topping off old R12 which you could do with your one can. That assumes that your system is still holding pressure. Connect your AC gauge and see what the system pressure is even without the compressor running. If you still have 20-30PSI after four years it may be worth "just" recharging your system.
That is where the mind game is starting as if you lose Freon you will also have lost compressor oil. A charged system is almost all but impossible to fill with oil unless you have special tooling for doing this. If the car is a beater it is not worth changing over to R134. Convert it if you have a nice car and you want to keep driving it without having to break a sweat in the summer (also, gas engine models had a fuel cooler that was using the AC evaporator return line to the compressor - it prevents fuel vapor lock). This is where you can spend a bit of money and you may be able to save a little here or there depending on how handy you are. Key to successfully enjoying cold AC even at engine idle is a compressor that is in top condition. If your compressor is only a few years old with very low miles/ hours on it you should be ok just replacing the O rings. For what exchange compressors cost to me it is worth just going with that and saving a lot of worries later. Plus, new compressors are typically already ready to run with R134 and are filled with Ester based oils. Then you need to pay attention to changing all the O-rings (the ones to use will be green in color). Flush the system one component after the other while you change the O rings. The most difficult component to get to is the expansion valve under the dash as per my video. Depending on who owned and serviced your car for or before you there can be copious amounts of debris in the system. This is especially true if lets say a compressor had failed before. I have seen a lot of junk come out of AC components and the expansion valve is very often plugged up with it - one of the key reasons even a fully charged system my not blow cold air anymore.
Use dry shop air to blow out the special solvent and then you can start re-assembling the system. Install the new dryer last and put around 1-2 ounces of new compressor oil into it before you seal everything up. Do not forget to install a conversion low and high pressure adapter fittings (car parts shops have them). Now rent yourself a high vacuum pump and pump down the system to full vacuum. In the first couple of minutes shut down the pump and see what your vacuum gauge does. The needle must not move. Otherwise you have a leak somewhere. I usually keep the pump running for at least half an hour. This makes sure you boil all the moisture out of the system. That is a really crucial step quite a few folks overlook and moisture in your system will diminish your AC's capacity to cool. Charge the system with regular R134 and place a sticker (provided with the conversion fittings) near the car build tag so techs working on your classic Benz will be able to more easily work on your car.
If you are not comfortable working on this system you can indeed ask your local Benz shop. You can also deploy FB and ask in the W126 group for recommended Benz AC shops in your area. Successfully converted cars are easier and cheaper to maintain, are environmentally friendlier, and the cooling capacity is almost up to par (the cars I converted would blow cool air even in 100F stop and go traffic). While the car in modest traffic and highway speed you will not be able to tell the difference. I am hoping this will help you. Good luck!
I believe there are direct replacements for R12 gas that is just as good and no conversion required
@@straybenzes Awesome in depth info!
Thanks! @@sonofprince4124
What if I jump those 2 wires and clutch does not engage ?
Next thing to check is the clutch itself. Look for the single blue wire going to the compressor clutch and connect it to plus. It should engage. If it does the next most probalbe cause for not working can be the Klima really. Change it out with a working one if you can. If that does not work then this may be due to a mulfunctioning ACC automatic climate control unit. Good luck!
@@straybenzes thanks a lot! I'll definitely try it.
Good luck! @@tone45.
great information you remind me of my grandpa.
Ha, ha. That is too funny. I am glad you liked the video.
thanks for the tip on the tools
Hoping that it will help you. All the best.
Hi friend. How do I check the A/C mecerdes W124 suddenly does not work. Because the A/C is not cold.
So the compressor clutch does engage with the AC on? If so, then you "just" do not have enough of a charge in the system. If the clutch does not engage put a wire jumper on the low pressure switch on the AC dryer. If the clutch engages then you had a leak and do not have enough gas in the system. You can opt to just recharge the system, but I will caution you that when gas escaped it will likely do that again. And when gas escapes then oil does escape with it. If your system is totally empty I would check an top off the oil in the compressor. Many compressors get damaged from running without oil. Put a good vacuum on your system before recharging. Good luck.
hi, big fan is that condenser fan? will be fit on w124?
I am not totally sure what you are asking. This fan is the single fan of the older W126. Later models had two fans. The W126 fan(s) will not fit on W124. Good luck.
I have a 1989 190e and the aux fans do not turn on. I have put 12v through the fans the switch and they all work. I have replaced the relays as well and still nothing. I need to fix this now because the summer heats are hereee!
Start the car and put the AC on max. Put a jumper wire on the high coolant temp switch. If they turn on then there is nothing wrong with them not being on. The main fan provides enough cooling air until the coolant temp gets too high.
@@straybenzes Unfortunately, they do not turn on which causes it to overheat.
@@Wake_up_01 Please post if and when you find out what was wrong.
@@straybenzes I just want to thank you! You know your stuff!
@@FashionOpticalDallas Thanks! There libraries filled with stuff that I know nothing about though. Good luck!
My friend why?
I did not record a video of its location or how to disassemble it
Yeah. I kicked myself for not doing that. It will happen again, but I do not have footage right now.
@@straybenzes I am very sad, my dear friend, and lately I have been unable to sleep because I have the same problem and I do not know how to switch between untying and tying.
I ask you to quickly make a video so that we can learn from you and solve the problem
Please help me, my dear friend
@@kalfoogaltmimi5043 I need to see if and how much footage I have of this work. I cannot promise that I will have anything and It may take a little while before I have another on coming in for this repair.
@@kalfoogaltmimi5043 Kind of disturbing comment
Hi
i just replace my compressor, condensor, dryer, thermostat at my local AC shop. But the ac only produce cold air at 21c with blower speed 1. I read the manual it should be 1-8c with outside temp 20-40c. and weather here is 32c average. What should i do next?
That is a loaded question. Is your system running R12 or R134A? Assuming it was converted to the latter, you can expect the AC vent temp to be in the 20C range with >30C outside temp - at idle RPM. While driving the AC vent temp should be closer to 10C. The AC compressor suction side pressure should be around 45psig with the AC on max and with the engine at 1500rpm.
Was the expansion valve also replaced by your shop? It should have been replaced during a R134A conversion. Its tiny orifice can block up with system debris and only replacement or rigorous flushing can alleviate this issue.
@@straybenzes sorry my bad, i forget to mention my car type. mine is 1995 G300 (M103 engine) its already r134a since brand new. My local AC shop did not change the expansion valve. and i expecting the expansion valve already 20 years old. my system has no leak, pass the vacuum test. but i already ask another pro Mercedes AC mechanic since 1998, and he said the nozzle on the expansion valve might be worn out. so he recomend me to change it, and i will D.I.Y the job.
do you have any advice for me? Thanks alot for the answer :)
@@mkwiipro5912 Well, do you have a Freon recovery system? Getting to the expansion valve and having the crow's feet wrenches is the biggest challenge. You will need to remove the instrument cluster, the center left console covering, and most likely a brace or two off the steering column. Good luck!
@@straybenzes in Indonesia (where i live) we are allow to throw away the freon to the atmosphere. And i will recharge my freon again with the same r134a. its only cost $30 for 1kg refrigerant (the amount of refrigerant, following the instructions for this car type)
and this is my 3rd time to completely opening the dashboard, so i hope it will be an easy job for me. And i also have a vacuum machine, since i also fixing a few AC system in my house. Thx for sharing, i will contact you soon again when i need help. See you!
@@mkwiipro5912 Good luck. I wish the world would recycle the gas properly. Good luck!
the AC is terrible in most German cars from the 80s... any way to upgrade them?
The AC is actually pretty decent. Only with R134 and during engine idle may it get a little warm.
Hey Ralf, Hope your AC is still going strong. What did you use as the cleaning agent?
I used this stuff: shop.advanceautoparts.com/p/interdynamics-certified-a-c-pro-power-clean-flush-1.06-lbs.-ca-compliant-ca-1/7010021-P?searchTerm=a/c%20flushes%20&%20solvents . R134 works pretty well in the last two that I retrofitted this way.
I have a 1988 mercedes benz 300 sel I replaced the air compressor,condenser, still not getting cold air, is the ac h block hard to do where is located
Assuming that you pumped the system down to a good vacuum, charged the system with the correct amount of refrigerant, and there are no leaks then a possible culprit could be the expansion valve or the evaporator. Do you have an AC hose / gauge kit? If so, what is the low and high pressure before and after your compressor? A faulty expansion valve and / or evaporator will mess with those values and you can pretty much isolate the trouble.
I need your help.my w126 ac is working fine on low rmp speeds.but when hitting gas pedal the air flow getting very slow you can hear the ac as it is choked.
Hmm. I need a little clarification about what you wrote. When you say that the air flow is getting slow is that referring to the cabin air blower?
Also, can you please describe what you are seeing, hearing, or measuring when you say that the AC is choked.
Yes the cabin air flow getting low vs acceleration .and when this happens I can hear the blower as it is circulation inside the dashboard but no air is coming out of vents.
@@Mohamed61110 That actually is related to either the climate control unit, the cabin air temp sensor blower, the blower motor, or the blower motor resistor. I would start with taking out the main blower motor and inspect the rotor and brushes.
Just FYI I noticed when this subject Start the economy guage started to stay on middle while normally it should stay on zero if car is on idle.i was guessing it might be some vaccume leal.
@@Mohamed61110 That should be an unrelated issue, but it is another issue that will need your full attention. If it is a vacuum leak close to the engine it should run idle and run rough. It could also be a leak closer to the instrument cluster.
*Fantastic video like always*
Thank you! Have a great and healthy Easter holiday.
My w124 is blowing hot air when I turn on AC. Can I fix it myself? Thanks.
That is a loaded question. If you have never worked on cars and / or AC systems I would recommend not messing with this system yourself. First step would be to measure the pressure on your system. Has it been converted to R134A yet? If so, then you can measure the pressure using a commercially available R134A refill kit. Connect it to the low pressure side of the AC system. Here it gets to be tricky. If you still have pressure, but just not enough to satisfy the low system pressure switch setting then you may be able to "just" recharge your system. If there is no pressure left I would stop right there because of two reasons: You will need to find the part that caused the leak. The second reason is that when you lose gas you also lose compressor lubricant. So "just" recharging the system may get it to work again, but you typically will run the compressor dry causing it's catastrophic failure. All that debris can also go into you evaporator and expansion valve. The latter is REALLY labor intensive to replace (you also need calibrated Swiss Army knife fingers to get there). Your call!
@@straybenzes OK so how do I lubricate the compressor? I couldn't find the heater valve.
@@alanOHALAN You can only add oil with the system completely and properly emptied of Freon. You have to disconnect the compressor intake line in order to add oil. This is not a job for novices.
What do you mean by heater valve? The mono valve?
@@straybenzes Yes the mono valve. I have the E300D diesel 1995.
@@alanOHALAN There are a few videos about the mono valve and how to fix it. In short I would get a cheap replacement valve and just use the rubber part. Replacing it on your old one (hopefully it is still the OEM part with the correct spring in it) is your best and perhaps only choice as OEM parts are no longer made.
You are a master. Thanks
Thank you. I do know a few folks who would beg to differ. ;)
Hi Ralph just curious when you remove the evaporator/expansion valve from the W126 with manual knobs did you remove the entire dashboard or is it accessible from below? Thanks!
You will need to remove the instrument cluster, carpet runner, center console side paneling on the driver side (LH drive), and the under dash cover. Then you need to loosen the black support bracket bolted to the steering column. In order for the bracket to move more freely you will also need to loosen the black wire zip ties. It is a pain to get to and super tight. Without removing this support bracket you will not get the crow foot wrenches to fit. Tighten every fitting by hand - the four expansion valve threads cross thread easily. You also will need a little extra foam as the foam wrapped around the expansion valve will likely just crumble on you. Good luck!
@@straybenzes thank you! keep it up...
Stray Benzes Good Afternoon, I have a 91 300 SEL. I’ve put dye and sealant in the system three years in a row along with a full charge of Freon and there’s no visible signs of leaks with the UV light under the hood. The cold AC will last the entire summer. After watching this video I have a feeling it’s the expansion valve...what else can it be? 🤔 I had an issue today after putting a full charge of freon..... The AC system was blowing cold air yesterday and this morning I was getting no air or cold air out of the vents. The compressor and blower do work....ran direct power. After watching your video I feel like I should replace the drier, the ac pressure switch and sensor (the red one with wires and the one with a bolt & to male connecting ends). I had my friend remove all the Freon from the system. The only part that I’m concerned with is replacing the expansion valve...... I have a feeling that many places would know how to do it.
@@4423Scott You definitely have a leak in your system as you should not have to top it off every year. Is your system running on R134? If so, were all O-rings replaced during the conversion process? If not, that is where I would start. Also, remember that if you lose gas you also lose oil in the process and you run the risk of locking up your compressor. Many folks just switch over to the new gas type and overlook the condition of the compressor. Swap it out if it is older than 5 years and use Ester based oil with R134, The expansion valve and evaporator inside the cabin can definitely be the culprit of losing your charge. I would take the UV tool and inspect that area. If you used dye I would imagine you would see that leaving residue in that area as well. I will put an excellent tutorial on the removal of the expansion valve in the description of the video.
Hi Ralph! Awesome videos!!! I just got a 88 420SEL and it was told to the previous owner that the problem was the condenser. How can I test the condenser? I already unmounted, but saw your video of yours after I ordered from PatsGeek! And wanted to shoot myself. And yes they sent me the wrong one too. Sending it back it is more expensive than the buying price, so I used it for target practice!
Oh no! That was unfortunate. The only way that a condenser would be a problem would be if it was plugged. If you use compressed air on you old one and air comes out unobstructed than it was not the condenser. If you have the system apart you might as well flush the system one component at the time - don't leave everything connected and then use only the two hose ends to do a flush. The biggest pain is getting to the evaporator and expansion valve. Make sure to check up on compressor oil - yeah, another pain in the romp to do that. Install a new dryer too; those are cheap. Fill that one with a little less than an ounce before closing the system. Putting a solid vacuum on you system to make sure you get all moisture out and that there is no leak is really important before charging the system. If your system still gives you trouble you can use the high / low pressure gauge kit to figure out which side is not working correctly. You would have to recover the Freon again though before you can work on it again. Good luck!
Where are you located?
South Eastern PA
@@straybenzes I'm in Florida I'm gonna come bring this car to you for you Master inspection
@@RentzSosa Pierre Hedary in Titusville FL may be a lot closer to you
How close are you to philly? Or new hope pa?
I forgot...Same 1985 201 190D 2.2 ..it is pumping cold air thru the center and warm air on the side vents. Blend Door issues maybe? for side blow of warm air? Totally
confused? All of the climate control switches and buttons all seem to operate CORRECTLY. Totally confused where to look at now?
To me this sounds like an issue I have read about here: www.peachparts.com/shopforum/tech-help/301897-1992-190e-2-6-why-warm-air-coming-out-sidevents-when-c.html
Hi sir,thats nice car you have,i know well how to fix that issue you have and you will be suprised how its going to run
Good luck!
When I turn on the air-conditioning in my w124 there is smoke coming inside through the vents. What causes that?
Hmm. What is the outside temperature and humidity when this happens?
Gentel man.. Thank you very much
Thanks and I am glad it helped.
I have a 1988 560 SEL. My A/C clutch engages on a cold start for 30-60 secs then disengages. I just put more R134 refrigerant and I'm at 45 psi on the A/C Recharge gauge so I know it's pressurized now. My clutch still won't engage but everything else seems ok. Like the Auxilary fan works, I hear different clicks and sounds when I switch from A/C mode to Hot air on the climate but I cannot figure out why my clutch will not engage even though it starts ok. Does anyone know what the problem could be?
Do you have an AC hose / gauge kit or just the low pressure fill hose and gauge that comes with new refrigerant cans? If your system was charged and you had to top the system off that is already not a great sign.
Based on the info you have provided there are still quite a few problem possibilities. It would be best connecting an AC hose / gauge kit. This way you can monitor the high and low pressure side of the AC circuit. Even if you only have the fill gauge off the AC freon can it can already be enough to literally see what the problem may be. With the AC set to max and the temp wheel set to max cool take a reading of you low pressure circuit. Watch what happens when the compressor kicks in briefly as you described. If the pressure goes down and the clutch disengages there is likely still not enough refrigerant in your system. It would be great if you also got a reading from the high pressure side. If the high pressure side rises in pressure and the low side keeps dropping pressure the expansion valves or worse the evaporator may be blocked. If you have to fill more Freon into your system please mind you that you may be running low on compressor oil also. Losing gas also means losing oil - you can lock up a compressor and if you are lucky before you burn clutch and CCU.
Another quick test you can do is jumping the low pressure AC gas switch S31 at the dryer. Take a set of alligator clips and jumper the two wires. The compressor clutch should be engaging. Do not test this for too long - you may ruin the compressor. Good luck finding the gremlins!
Stray Benzes My guess was that there is a leak somewhere. The issue is that I inherited this car from my grandmother after she passed last year and I think the last time the A/C was touched was when it was converted to support R134 in the 90's. So when I recharged it the low pressure was at 0. So it seemed like there was no refrigerant left. Now it's at 45 PSI. All I used was the recharge because I thought adding some pressure would jump start the clutch again because of the sensor but it didn't work. The clutch only comes on when the engine is cold only for 30-60 seconds. Not sure why. I definitely need to get a compression kit. I just don't want to buy a new cmpressor because it actually seems fine. It seems like there is an electrical issue or something. Or it needs a new clutch. How do I add the oil in? Do I add it to the low pressure line?
@@quiltingrox Good news is that you have the history of the car. That info in worth gold. With that said I would get the system leak checked and then get the system evacuated again. If the car has sat around and the AC system has been without pressure for a while you should pull off the compressor and drain what little oil may be left. Flush the system component by component and then dry it out with either N2 or super dry shop air if you can. Use new R134 Orings throughout and then install a new dryer. Make sure to fill compressor with enough oil and put an ounce into the dryer. Pump down the system with full vacuum (I did forget asking you if you did this prior to filling freon into the system) for at least half an hour. You should do a leak test with vacuum before filling the system with new freon gas. It may be a good idea letting a shop you trust do this work.
Stray Benzes ok thank you for your help! What I do know is that the leak is super slow and small because it holds pressure very well. I have to think that there was a leak since the 90's and it finally drained out this year. How do I add A/C oil?
The new compressors come with pag oil fills
Most of them do. Thanks!
My 126 sometimes kicks on the dual auxiliary fan when i only turn on ignition why would that be Ralf._. ?
When did this start happening? For how long have you had this car? Is this happening with a cold or warmed up engine? Is it running in low or high speed? This could be the high coolant temp switch or the Klima relay. If it only happens with a hot engine it cold also be because the coolant is indeed that hot that the high temp switch engages.
Hello Ralf just an update and a detailed description of the problem with the old girl I have it since 2010. It is a 300SE 1990. The problem started one morning when I simply went out to start it turn the ignition on and before i cranked I heard the aux fan come on the engine was cold yes... This is strange right.. So I went out to see what was happening and noticed only one of the two fans were working theres another problem probably motor worn.. it is not fuse a fuse is changed and new but there suppose to both work in harmony and kick on together as the wires parallel. so my guess is its the motor on fan that's shot. A little test I done was on the CTS I disconnected it with ignition off then on. and it came on but just the one fan that only happen when car was cold too if warm that test doesn't work. I would higily appreciate you doing a video on the aux fans mine is a 1990 model so it has the upgraded dual fan set up but It looks like a PITA to remove with them plastic pop rivets on the shorund and access looks teribble to take the whole unit off the change the fan. Now I guess I have to say that il be honest that my A/C has been neglected as I havent converted it over to R134a only thing I done to it in regards to A/C was change the blower motor as the brushes were wore and it started squealing. I wasn't able to get a direct replacement though as there NLA. Other thing is I didn't know theres a modification you can make to the CTS to make them cut in at a lower temp. May look into this when I consider taking on the aux fan removel.
@@ZaneTravel233 Looks like you have two separate issues. One fan seems to be defective. Both are indeed wired in parallel and should run together.
The other issue is that they are operating right from turning the car on. With AC on they are supposed to do that, but only in low speed.and with the high freon system pressure switch engaged. The high speed fan setting is controlled by the CCU that triggers based on the engine coolant temp sensor. Is your fan spinning at high or low speed? Fuse 5 is the main fuse for the high low fan speed relays K9 K10 and both of those get control voltage connected to air injection relay K17 (not controlled by it though). All of them sit in the main fuse box. I would check what the fan speed is next. Good luck!
Most confusing issue: 1985 W201, Diesel 2.2. Made a TOTAL and complete removal and replacment of every single hose, pipe, tube, , compressor, condenser, pressure switches , drier, expansion valve ...converted to R134 even electrical connectors for the fans . EVERYTHING. NOTHING of the old system remains. PROBLEM, The high side reads low pressure and the low side reads High pressure. Its like the compressor is running the opposite direction. ???? R134 was installed by weight as it should be..?????
Interesting. Why did all of those components have to be replaced? I usually only fix what needs fixing and usually only replace the rubber parts and expansion valve. Assuming you did everything correctly I would say let's start with the pressure values you are reading on your gauge assembly. What is the system pressure without the engine running? With AC on Max and engine running what are the pressure values on the high and low side ports?
thanks man! Subscribed
Thanks!
Hallo buddy cheers for the great knowledge you share 💪🏻👍🏻
Gab
No problem 👍
@@straybenzes hi, so on my 300 td wagon I changed out the filter drier, expansion valve and compressor, the compressor clutch wont engage I also checked fuses, maybe a relay problem?
@@Decimusblack88 Try jumping the min pressure switch mounted to the side of the dryer and jumper the contact with the AC on and on min temp. If the clutch does not engage it can be the air conditioning relay and / or the ETR switch. Good luck!
@@straybenzes thank you I will give it a shot in the morning :)
@@Decimusblack88 Good luck.