During times of higher intake manifold vacuum (idle, cruise, deceleration) and thus lower crankcase pressures, the PCV valve activates, creating a metered draft to draw the crankcase vapors into the intake manifold vacuum port via the PCV valve hose (aka "ported" vacuum). During times of lower intake manifold vacuum (acceleration) and thus higher crankcase pressures, the PCV valve deactivates and the crankcase vapors are then pulled into the air intake tube via suction (aka "venturi" vacuum). Note the consistant vapor-drafting overall, but in two entirely different senerios and directions. Truly a simple but brilliant design once fully understood. Hope this helps. 😃
@@hanc37 Nope! I just removed 2 PCV valves to clean for my relatives. They both rattled and they both allowed air to pass through both ways. What I'd like to see in this vid, is what will happen if you had a bad PCV valve.
Dude pulled my sons off and it was broken inside ,I put hundred in parts trying to fix my sons Chevy blazer and all it took was your video and this lil 4$ part and it’s fixed 😍 at least I gave his car a free tune up 🤣 thank you brotha your the man 👊🏽
I've got a 87 R-20 Chevy Surburban w/ a 350 throttle body I've notice one morning I, went to check the fluids like I always do before starting any engine I notice that the pvc valve was laying on top of the right top of the valve cover which came out of the pvc hole so I took the pvc valve off of the rubber hose and shook it and their was no rattle sound so I clean the pvc valve with mass air spray cleaner and put it back in to the hole on top of the right valve cover and rehooked it back up to the rubber hose after that I had not had any more problem with it blowing out any more
I've been around cars for decades, and I'm quite familiar with how the basic systems work, but every once in a while, I like to watch an explanation video just to see how well somebody does presenting the info. This was superb, clear, concise, simple for anyone to follow👍
He did a great job for those that don't know, replacing your pcv valves are so important it might be a small part but it plays a very important role in your engine. Do not drill bigger holes in your valve
This might be the greatest explanation of crankcase ventilation I have ever seen! Not sure what your career decision is, but you should be in an automotive classroom. Thanks, brother
I’ve been researching PCV systems for awhile now with the intent of picking out a catch can system and haven’t really found great resources... This video is excellent! It very clearly explained how these systems work, thanks!
Very well explained. 😃👍 You just forgot to mention 2 things/functions: - At high revs but closed throttle it's necessary to restrict the flow for avoiding the PCV-valve beeing a bypass around the throttle. That's necessary for revving down. - In case of a backfire into the intake system the pressure rises spontaneously, so the little piston in the PCV-valve is pressed backwards, shutting completely with the plate against the washer. This is for avoiding the backfire entering the crankcase and damaging the engine. That's all. I had never seen a cut open PCV-valve yet, just drawings, but not in real. 😉
@U.E. U.E. Can you explain how a backfire into the intake is caused? I’m repairing a 2021 Traverse (w/114 miles) that caught on fire from an intake backfire that melted down most of the plastic intake “duct” and burned the side of the engine that faces the radiator. Have the wiring harness and all melted parts replaced and am ready to start it up, but need to find what originally caused the backfire. Any ideas?
@billcowhig5739 In the case you worked on the engine the most likely is to mischange the ignition cables and having the spark during the intake stroke with open intake valve (I did it once in a boat, mischanged 1/4 and 2/3 - boom! 🤦♂️ The oil filler cap was shot vertically up, passed so close by my head that I felt the wind in my hair and shot a hole in the roof above me.). Other reasons can be excessive amount of fuel in the hot intake or ignition/valves very far off.
I'm having oil leak into my air filter and I read it might be from a bad PVC valve. I literally never heard of that or had any idea what it was but now I understand. Still not sure if it's what is causing my problem but I think it a good place to start. Amazing explanation that even a non-mechanical person like myself can understand. Thank you!
I just found your channel, and I noticed that you haven’t uploaded since last year. You explain things in a way that’s so easy to follow! I hope you’re doing well. Thank you so much for such awesome content 🙌🏻
Wonderful, you had my attention without skip. They way you explained things verbally and visually was amazing! And now I can assume the result of my PCV valve hose being compromised, as it's not able to return those gases into the crankcase and thus a low MPG!!
I was paying too much on car repair , so I started to watch many of you guys teaching the work in mechanics, And Im very thank full to all of you , Because I've been doing a lot of work on my cars, And it became fun after the results" Thank you again.It is a blessing .
If this explanation does not help you understand the complexity of pcv system, I do not know what will. Thank you sir for taking all the time and effort to simplify this system for us
What a beautiful video is this. The more I know about how modern car works the more I become interested and wants to learn more. Not only how pcv works but also how you explain it are pleasing. Thank you buddy.
Excellent demonstration video. I now realise the importance of this valve. Recently noticed my idle slightly higher than normal & increased engine oil consumption. Checked pipes/hoses etc... for vaccum leaks, no leaks. I checked my pcv & its jammed open 100%. Now going to purchase a new pcv valve. Thankyou very much. 👌🏻👍🏻👏🏻👏🏻👏🏻 👋 🇦🇺
Thank you for making a great video! I am an automotive instructor and we watched your video in my class and talked about it. It was very informative and I love the way you showed the cutaway of the PCV valve itself.
Your telling me!!! I had an oil seal burst on my bikes engine today because I disconnected my PCV from my intake a while ago... how dumb of me to do 🤦♂️
Sir, Thank you in your explanation on how PCV works. Great detail information and very articulate. If we all had instructors as yourself, we would all be Master mechanics. Once again, Thank you!
Thank you for this video; it makes perfect sense. I have a forced induction 2v modular ford that is converted to non-emissions, non-cat, non-egr, etc. that runs a blow-through MAF. I currently have a PCV and one breather on the opposite valve cover (the inlet side) and started thinking better of it. After finding a mix of information online about it your video lead me to a bit of a shift in my thinking. I now realize that I have a pretty serious unmetered air condition going on. My car idles a bit erratically; but my car also has a cam so it's somewhat to be expected. I do on occasion stall at lights and wonder if this has something to do with it. Time to rethink that inlet side I think; I'll just weld another port onto my intake tubing and connect the inlet side to that tubing (upstream from the MAF) instead of using that breather. Also thinking I could install a check-valve below the breather (would probably fix the unmetered air condition), but I wonder if this would increase my crankcase pressure, thinking that would be a bad thing.
Thank you for this video. I have watched several videos, read articles, and asked different people and couldn’t understand how the PCV system works. This did it for me. Excellent job, thank you so much!
Thank you. it would be even great if you could add two more focuses in each lesson: 1. at the beginning, introduce:: what symptoms we can "see" or know that the PCV valve is failing or filed. 2. in the end, comments on: :what would happen or get affected, if this PVC (or part) stayed in failed condition.
This helped me understand the pcv valve a bit better. I recently replaced my old pcv valve and a few days ago I got a P0402 Exhaust Gas Recirculation Flow Excessive Detected code for my 96 Ford Explorer. I cleaned my pcv valve today and it got the engine code to go away. So glad I didn’t spend a bunch of money for a simple cleaning in the pcv valve.
I remember my 55 Chevy 265 V8 with the crankcase draft tube facing the ground to vent the hydrocarbon gasses. It would stink in the Summer when it ran in traffic. My next newer mid-1960's car had the PCV system and did what it had to do as you had explained. But one thing that you did not mention was that with the PCV system the engine actually got better gas mileage as well as the cleaner air to breathe. Because the metered unburnt blowby hydrocarbons were reburned when sucked into the intake manifold along with the air fuel mixture for extra fuel efficiency.
Great video Sir! I suspect many DIYers have no idea what the internals of the PCV valve are, but now they do if they watched the video. Thank you for the elucidation.
Excellent explanation of the PCV valve. I am building a custom engine and have seen many variations on how to control crankcase pressure. I'm installing an EFI system and was thinking of going with venting to a can, but now I think the best way is to run it into the base of the throttle body. I don't want to run it in such a way as to add oil sludge at the intake valves. Great job, thanks!
Excellent knowledge here. .. As the plastic PVC housing on the plastic valve cover, the new valve would not seal properly on the engine vacuum side. I plumbed the pcv valve to the other valve cover, to the smaller hose fitting, then to the manifold inlet on the other end of the hose. .. The air box vent hose went to the larger broken side, with a minor repair. Everything worked great.. Thank you for this video.
It actually makes sense when someone who understands it explains it. I was trying to figure out the oil looked thin and smelled like fuel in the crank case and the intake. If you have problem with the PCV you have to check the vacuum, throttle body and the air intake. I have seen a lack of knowledge in this area end a few cars. How does the EGR fit into the mix. If you have negative pressure the fresh air intake to crankcase is plugged?
At the end of the following there's a point and lesson about a PCV valve: I have a 2002 Toyota Sienna with 230,000 miles on that just lost its #5 cylinder ignition coil. Two of The front ones already went. But those and the spark plugs are easy to get to. Well so with the rear coils and plugs when you have to take off that intake platinum. My mechanic is a friend who's retired from active mechanic work and now works out of his house at cut rates for friends, but it still cost enough. So I Wasn't going to fool around with anything aftermarket. Back there, so I hadn't put OEM Denso coil packs in the rear. And I put OEM Denso iridium 100k mile plugs all around. I got the car in 2012 with 136k on it and I just had him do the plugs back then with the NKG equivalent of the Denso iridiums. So those were fine. But I feel a little cheated because now they only had 65.5k on them. 😄 But also back in there the PCV valve, much less at it's grommet, Is not easy to get to. oh, sure, everybody might have their little tricks to reach it and do the job. But that's if everything goes smooth. But in this case, even with the plenum off and full access, it did not. For one thing, when I first got this car in 2012 and had him do the tune-up, I didn't even consider the PCV valve. That was a major F up...as it now seems that it was the ORIGINAL. So, when my guy went to remove it, to pull it out of the grommet, It was so brittle it's snapped off flush with the grommet. He then used his needle nose pliers to pinch a section of the PETRIFIED grommet and try to remove it from the whole in the intake manifold. At which time 3/4 of it that was below hole broke off and drop down inside. Between us taking turns it took us nearly an hour to get it out of there. It was in one large chunk with no flaky pieces, and he pretty much suggested just leaving it in there because there was nowhere for it to go and it wasn't going to get sucked into anything as big as it was. But it's size and shape also prevented it us from getting it out through the hole with pliers or hooks. He finally got the idea to spear one end of it with a Instrument that look like a broken dental pick and rolled it up through out of the hole like that. But the bottom line was that PCV valve was pretty cruddy and I'm sure it was poorly functioning at best. And I think that because of what I have since learned about What PCV valves do and how they work in relation to pressure in the engine. When my mechanic pulled out my coils and my spark plugs from the back there was a little bit more oil on or around them than there should have been. Not awful, but time to think about a head gasket sometime in the future. Well, I'm sure that's true in a car that old. But I'm also thinking that If that PCV valve was bad and the pressure had built up in the crankcase, that might have exacerbated any problem like that pushing out oil where it would not normally have escaped from and something like a head gasket job might not really be an imminent issue now that the valve is replaced. IDK. But maybe. Also, and I don't know if this is a thing, but I seem to have a noticeable amount more giddy up and go with seemingly less effort. Again, don't know if that's the PCV valve ffully functioning or not over a clogged one. I doubt it's my coil packs and new spark plugs. Those either work are they don't? Also, because my PCV valve in this car was hard to get to I went with a genuine Toyota OEM one from the stealership. Same with the grommet. I researched it online. And too many people made too many good points about aftermarket ones not necessarily being 100% calibrated specific uses in that they have to fit so many makes and models of cars. So yeah, for the peace of mind it offered me for such a very simple yet very important part, It was worth it. Moral of the story (mini novel 😁): 1. Don't overlook the PCV valve. 2. Don't skimp on quality. ones or the right fitment. 3. Replace the grommet at the same time. 4. Do not waste time cleaning them INSTEAD OF replacing them. If you like only do it as a general maintenance thing to keep them unclogged. Like if it's easy to get to and you want to do it every other oil change or something like that. But the SPRINGS wear over time and lose the appropriate tension. So it can rattle and still be fucked up. Best to all and thanks for this video.
I am hoping this is the fix for my 1985 Prelude which I was stupid not to start up for a year. It backfires now and revs shoot up on start up so having changed leads to plugs and coil and thinking this may be the cause...if I can locate it. I have a manual but although it recommends that it is replaced every 30k it doesn't show its location. Having watched this I should be able to locate it now. However getting a part for this car in the UK that is original manufacturers is near impossible...just seen someone selling a distributor cap for £100! Luckily I found a couple new in USA which were cheap so got my freind to buy and send over!
Excellent video Sir. Another thing that is taking place is at long idle times, the crank case pressures are also allowed to vent into the intake tube behind the throttle blade. That particular tube really serves two purposes. Great job with this video
Thanks a lot for a clear explanation. Now I learned at there is actually cleaned fresh air coming into the crankcase, and then there is a pcv valve which regulates the vacuum in the crankcase. I will rush to my Engine bay to see my own vacuum system.
Very informative and straight to the point sir! The illustration on the white board was perfectly executed as well! Oddly enough my engine does not use the traditional style pcv valve, it uses what seems to me like a flow restrictor and a smaller vaccum hose for this portion of the crankcase venting. The other portion which is a larger hose connects, How you described after the maf before the throttle plate. My engines valve cover only has one fitting that attaches to it and it’s basically a “T” adapter with two hose barns on the end. One for the larger fresh air hose and one smaller fitting that goes and connects under the intake manifold. I’ve been trying to install an oil catch can to minimize the amount of oil building up inside my intake manifold. I know my best option for maximum performance would be to vent all this to atmosphere which I have done in the past previously on the race track but if I’m daily driving the car it smells like crap and vapors are pretty strong since I do have a higher mileage performance engine that’s due for pistons and rings when I’m in a better financial state. When installing an oil catch can in line with my cars system it seems like I must install a can “in-line” with both the smaller and larger hoses ? I would cause alot of damage if i deleted the smaller hose in my system that’s pulling the crank case fumes during idle eight ? I’m just trying to understand and be sure before I spend extra money. It sounds like I need to install two seperate catch can…..one for idle and vaccum state and the other for wide open throttle conditions 🤷🏼♂️
Yes I remember, I was a boy then and driving behind a vehicle I saw the tube spitting out the gasses on the road, it's interesting to be learning about it now after all those years.
I like guys like him... good talker, plain speaker, and lots of mechanical skill and common sense... PCVs are cheap and easy to replace by yourself and are simple to overlook!. Mine can be thoroughly cleaned with parts cleaner and replaced or a new one is a few dollars and easy to install on my 2000 Corolla....
Gotta say, this is the best damn explanation ive ever had the chance to be present for. No room for misinterpretaton whatsoever. I even had the spring actuation behavior straight nackwards in my mind for awhile now, thinking that vacuum was acting in the complete opposite direction. No wonder i was confused. Right on my bradda, myth busted! Mahalo!
Great video. I’ve been trying to make my car run better and this is one part I’ve overlooked for a long time because I thought the PCV valve didnt do much. I’m about to change the valve cover gasket which has been losing some oil lately, now that I know about the crankcase pressure thing I’ll do the PCV also.
Started watching this after I replaced one in my Honda. Just shake it to see if it rattled. If not, replace it. I didn’t think it would make much of a difference, but it did. It doesn’t run Rich anymore and mpg shot up. Car runs great and it got its power back. Check it every oil change. It’s a$3 part that really helps.
Also what's important to note...the pcv valve hose always goes to manifold vacuum and the opposite side of the system goes to pre vacuum (air cleaner) before throttle body or carb. I've seen people do it wrong.
Very clear easy to understand explanation must have watched 10 vids on this subject and this is the only one that was detailed and I was understood completely... thanks...
Awesome explanation man, thanks. I kept hearing a buzzing sound on my Silverado inside the engine bay on the driver's side. It was making me a little crazy. Turned out it was the check valve in the pcv. No big deal, just annoying.
Hi Kyle I see that the direction of the PCV flow is from the air-box through the breather filter to the crank case, to the PCV valve and so on; what I'm trying to understand is how does oil end up in the air- box which is opposite to the flow, and why isn't the breather filter preventing it from going to the air-box?
thanks for the video.....i was having issues with my car and saw another video that mentioned the PCV system, i dug deeper and on my honda civic it was easier to change the PCV valve than it is to change gears....so i did it....the guy at the auto parts store said these should be changed once a year....but that seems a little exessive.
Thanks everyone for checking out the video. If you liked this video, we have more videos on Emissions Control Systems and many other videos you might enjoy about the Automotive Industry.
Thank you for this. I now understand how the PCV valve system creates positive ventilation. I was thinking of installing a catch can realise now I'd better do more research first.
Best explanation I've seen. The cutout PCV really solidifies understanding. I was only looking for a refresher since my classes were in the 90's, but got a really deep understanding of the system. Wish my teachers cared this much. Thanks for the effort.
My Mx5 was spark-knocking and smoking like crazy- took it into a shop, they did a compression test and cleaned the fuel injectors and told me to run higher octane fuel, charged me $465 and didn't even solve the problem. I installed a new OEM PCV valve, and voila, corrected the problem, has never run better!
Thank you so much! We replaced my pcv valve... old one was horrible looking, I noticed sludge on last oil change, terrible gas mileage, oil around my coil packs, leaking small amounts of oil under the engine... Anyway it all was a hot mess! So now we put the new pcv valve in and test drove - when I came home at an idle there's a loud rattling sound. Where should I go from here?
Your video is a lot better than one I just saw on u tube !, that other video didn't even explain how the pcv valve works!!, also one question, all of the pcv valves I see these days either don't have anything in them but a small hole, or they have a small hole and a small stainless steel ball that rattles when you shake the valve, can't find any like the one you cut open ? Can you please send some information on where the spring controlled valve can be found? Thanks 😊
I really enjoyed the way you explain. And it is easy to process information, coming from a person that just started doing DIY stuff to enlarge vehicle lifespan. Great job!
Great video!!! Liked and subscribed!! I always wondered the specific function of a pcv valve, I'm replacing mine but it gives me peace of mind to know that's most likely my issue based on the symptoms and everything else being replaced. Cheers!!
Great explanation on part throttle and closed throttle operation of the PVC. At WOT (wide open throttle) when there is least amount of vacuum, the spring pushes piston down onto opening effectively closing the PCV inlet. Its a neat little valve that works in 3 modes with only 2 moving parts.
i remember those tubes during the 60;s they ran down ; always wondered why my dad cleaned them from time to time < old cheavy 1962 straight 6 cylider , she was a truck and a tractor it seemed .. thanks awesome video ,,
Hi Buddy (master educated man) I watched many of videos, But for me no one explains as U, especially circulation of fresh air pushing blow by air out, The way after MAF sensor air circulating, God blessed U Buddy Amazing explanation, Amazing. 👍👍👍
Around 1960s, there was higher demand to control the smog. Therefore do not vent the the crankcase to outside, but to feed it into the intake. Problem 1, it was common to have engine back fire, or flame coming out of carburetor in the old day. Or tail pipe. If the flame enters the crankcase, it will pop the engine oil seals. Therefore the PCV, or an one-way check valve. Problem 2, the PCV has a dirty live and it can get clogged over time. You will notice it during high intake vacuum (low RPM or decelerate). Such as your engine will die when you decelerate around a corner. I am not sure if there is a modern high tech solution? But I have not seen PCV problem for over 15 years.
A little bit of preventative maintenance goes a long way to avoid serious, expensive repairs. Even if you have no idling issues or other symptoms, it’s just a good idea to replace certain critical parts after a specific interval. I replaced my PCV valve at 120,000 miles while replacing the water pump and drive belt. Honda recommends those parts be serviced after 100k miles.
Excellent! Thank you very much very professional very informative. It’s funny but every time I get an oil change I notice I have to put in about a quart within a months time after that seems crazy I just thought it was just burning oil because it was older. Now after doing some investigation and research and I know I can take action myself. So far I added some oil and a Lucas additive and it’s great. Then I clean the air intake valve and it works even better and now I will clean or replace this PCV valve. It seems crazy that this is the first time I think I’ve really heard of this.
On my 2002 Ford Focus, although it uses a MAF sensor, the PCV breather intake is not metered and the value is simply programmed into the PCM. The hose connects before the MAF sensor.
During times of higher intake manifold vacuum (idle, cruise, deceleration) and thus lower crankcase pressures, the PCV valve activates, creating a metered draft to draw the crankcase vapors into the intake manifold vacuum port via the PCV valve hose (aka "ported" vacuum).
During times of lower intake manifold vacuum (acceleration) and thus higher crankcase pressures, the PCV valve deactivates and the crankcase vapors are then pulled into the air intake tube via suction (aka "venturi" vacuum).
Note the consistant vapor-drafting overall, but in two entirely different senerios and directions.
Truly a simple but brilliant design once fully understood.
Hope this helps. 😃
I never leave UA-cam comments. I have never seen such a wonderfully simple explanation of how a PCV system functions. Awesome, sir!
I was gonna say the exact same thing, great explanation and illustrations.
@@donavanflowers4656 I never realized how important a PCV valve was. I always figured if you hear that valve rattle around... all was good.
I never read comments but your is the very first I've read 😃😃
@@hanc37 Nope! I just removed 2 PCV valves to clean for my relatives. They both rattled and they both allowed air to pass through both ways. What I'd like to see in this vid, is what will happen if you had a bad PCV valve.
He earns my credit for cutting the part in half for illustration.
Dude pulled my sons off and it was broken inside ,I put hundred in parts trying to fix my sons Chevy blazer and all it took was your video and this lil 4$ part and it’s fixed 😍 at least I gave his car a free tune up 🤣 thank you brotha your the man 👊🏽
What if they are stuck open I been chasing a maf code and I checked my valve and I can blow air threw both ways and there oil on the tube fans intake
@@arealmaintenanceandrepairl1103 same with me
@@arealmaintenanceandrepairl1103 they need to be getting vacuum through the tube that is connected to it
UA-cam do it yourself saves soooo much money
I've got a 87 R-20 Chevy Surburban w/ a 350 throttle body I've notice one morning I, went to check the fluids like I always do before starting any engine I notice that the pvc valve was laying on top of the right top of the valve cover which came out of the pvc hole so I took the pvc valve off of the rubber hose and shook it and their was no rattle sound so I clean the pvc valve with mass air spray cleaner and put it back in to the hole on top of the right valve cover and rehooked it back up to the rubber hose after that I had not had any more problem with it blowing out any more
Videos like this are truly priceless. The beauty of free information is one of life’s greatest things in my opinion.
I've been around cars for decades, and I'm quite familiar with how the basic systems work, but every once in a while, I like to watch an explanation video just to see how well somebody does presenting the info. This was superb, clear, concise, simple for anyone to follow👍
He did a great job for those that don't know, replacing your pcv valves are so important it might be a small part but it plays a very important role in your engine. Do not drill bigger holes in your valve
Why not? Surely that would allow the pressure differential inside the crankcase to equalise and perform optimally again?@@JOEY0872
"These things weren't designed to be cut open."
That right there got me to click the subscribe button. Excellent video.
This might be the greatest explanation of crankcase ventilation I have ever seen! Not sure what your career decision is, but you should be in an automotive classroom. Thanks, brother
I’ve been researching PCV systems for awhile now with the intent of picking out a catch can system and haven’t really found great resources... This video is excellent! It very clearly explained how these systems work, thanks!
Very well explained. 😃👍
You just forgot to mention 2 things/functions:
- At high revs but closed throttle it's necessary to restrict the flow for avoiding the PCV-valve beeing a bypass around the throttle. That's necessary for revving down.
- In case of a backfire into the intake system the pressure rises spontaneously, so the little piston in the PCV-valve is pressed backwards, shutting completely with the plate against the washer. This is for avoiding the backfire entering the crankcase and damaging the engine.
That's all.
I had never seen a cut open PCV-valve yet, just drawings, but not in real. 😉
@U.E. U.E. Can you explain how a backfire into the intake is caused? I’m repairing a 2021 Traverse (w/114 miles) that caught on fire from an intake backfire that melted down most of the plastic intake “duct” and burned the side of the engine that faces the radiator. Have the wiring harness and all melted parts replaced and am ready to start it up, but need to find what originally caused the backfire. Any ideas?
@billcowhig5739 In the case you worked on the engine the most likely is to mischange the ignition cables and having the spark during the intake stroke with open intake valve (I did it once in a boat, mischanged 1/4 and 2/3 - boom! 🤦♂️ The oil filler cap was shot vertically up, passed so close by my head that I felt the wind in my hair and shot a hole in the roof above me.).
Other reasons can be excessive amount of fuel in the hot intake or ignition/valves very far off.
Excellent video! 👌🏻 Clear delivery, nice illustration, no excessive rambling, normal human voice! 👏🏻👏🏻👏🏻
I'm having oil leak into my air filter and I read it might be from a bad PVC valve. I literally never heard of that or had any idea what it was but now I understand. Still not sure if it's what is causing my problem but I think it a good place to start. Amazing explanation that even a non-mechanical person like myself can understand. Thank you!
You can also pick up a oil catch can as well. So if any oil still slips by it will go into there instead of your filter.
Did changing the PCV change fix your problem? I’m having the same issue.
I just found your channel, and I noticed that you haven’t uploaded since last year. You explain things in a way that’s so easy to follow! I hope you’re doing well. Thank you so much for such awesome content 🙌🏻
That explains the function of PCV valve better than I've seen from others. Thank you.
Wonderful, you had my attention without skip. They way you explained things verbally and visually was amazing! And now I can assume the result of my PCV valve hose being compromised, as it's not able to return those gases into the crankcase and thus a low MPG!!
I was paying too much on car repair , so I started to watch many of you guys teaching the work in mechanics, And Im very thank full to all of you , Because I've been doing a lot of work on my cars, And it became fun after the results" Thank you again.It is a blessing .
If this explanation does not help you understand the complexity of pcv system, I do not know what will.
Thank you sir for taking all the time and effort to simplify this system for us
What a beautiful video is this. The more I know about how modern car works the more I become interested and wants to learn more. Not only how pcv works but also how you explain it are pleasing. Thank you buddy.
Excellent demonstration video. I now realise the importance of this valve. Recently noticed my idle slightly higher than normal & increased engine oil consumption. Checked pipes/hoses etc... for vaccum leaks, no leaks. I checked my pcv & its jammed open 100%. Now going to purchase a new pcv valve. Thankyou very much. 👌🏻👍🏻👏🏻👏🏻👏🏻 👋 🇦🇺
Thank you for making a great video! I am an automotive instructor and we watched your video in my class and talked about it. It was very informative and I love the way you showed the cutaway of the PCV valve itself.
very clear! A key maintenance item very often overlooked that causes engine seal leaks when restricted (80kMi)
👍
Your telling me!!! I had an oil seal burst on my bikes engine today because I disconnected my PCV from my intake a while ago... how dumb of me to do 🤦♂️
Sir, Thank you in your explanation on how PCV works. Great detail information and very articulate. If we all had instructors as yourself, we would all be Master mechanics.
Once again, Thank you!
Excellent training and explanation. I never thought that the pcv is actually 2 valves in one. Bottom part closes and top one meters.
Thank you for this video; it makes perfect sense. I have a forced induction 2v modular ford that is converted to non-emissions, non-cat, non-egr, etc. that runs a blow-through MAF. I currently have a PCV and one breather on the opposite valve cover (the inlet side) and started thinking better of it. After finding a mix of information online about it your video lead me to a bit of a shift in my thinking. I now realize that I have a pretty serious unmetered air condition going on. My car idles a bit erratically; but my car also has a cam so it's somewhat to be expected. I do on occasion stall at lights and wonder if this has something to do with it. Time to rethink that inlet side I think; I'll just weld another port onto my intake tubing and connect the inlet side to that tubing (upstream from the MAF) instead of using that breather. Also thinking I could install a check-valve below the breather (would probably fix the unmetered air condition), but I wonder if this would increase my crankcase pressure, thinking that would be a bad thing.
Thank you for this video. I have watched several videos, read articles, and asked different people and couldn’t understand how the PCV system works. This did it for me. Excellent job, thank you so much!
Thank you.
it would be even great if you could add two more focuses in each lesson:
1. at the beginning, introduce:: what symptoms we can "see" or know that the PCV valve is failing or filed.
2. in the end, comments on: :what would happen or get affected, if this PVC (or part) stayed in failed condition.
This helped me understand the pcv valve a bit better. I recently replaced my old pcv valve and a few days ago I got a P0402 Exhaust Gas Recirculation Flow Excessive Detected code for my 96 Ford Explorer. I cleaned my pcv valve today and it got the engine code to go away. So glad I didn’t spend a bunch of money for a simple cleaning in the pcv valve.
I'm glad the video helped you understand the PCV system and helped you take care of your fault code.
God damn! It took 5 years to find this gem!
I remember my 55 Chevy 265 V8 with the crankcase draft tube facing the ground to vent the hydrocarbon gasses. It would stink in the Summer when it ran in traffic. My next newer mid-1960's car had the PCV system and did what it had to do as you had explained. But one thing that you did not mention was that with the PCV system the engine actually got better gas mileage as well as the cleaner air to breathe. Because the metered unburnt blowby hydrocarbons were reburned when sucked into the intake manifold along with the air fuel mixture for extra fuel efficiency.
Great video Sir! I suspect many DIYers have no idea what the internals of the PCV valve are, but now they do if they watched the video. Thank you for the elucidation.
Glade to listen when someone is not talking 90 miles an hour.
Great vid
Thank you for cutting the pcv valve and explaining how engine vacuum affects the valve!
Fascinating. Over my head, but kept me riveted. I now have somewhat of an understanding of positive crankcase ventilation. Thanks 😊
Excellent explanation of the PCV valve. I am building a custom engine and have seen many variations on how to control crankcase pressure. I'm installing an EFI system and was thinking of going with venting to a can, but now I think the best way is to run it into the base of the throttle body. I don't want to run it in such a way as to add oil sludge at the intake valves. Great job, thanks!
Excellent knowledge here. .. As the plastic PVC housing on the plastic valve cover, the new valve would not seal properly on the engine vacuum side. I plumbed the pcv valve to the other valve cover, to the smaller hose fitting, then to the manifold inlet on the other end of the hose. .. The air box vent hose went to the larger broken side, with a minor repair. Everything worked great.. Thank you for this video.
Wow! Really well explained! Good drawing and showing the actual parts themselves along with using simple words to explain it all. Excellent video!!
Probably the best explanation on how PVC systems work. Good job!
It actually makes sense when someone who understands it explains it. I was trying to figure out the oil looked thin and smelled like fuel in the crank case and the intake. If you have problem with the PCV you have to check the vacuum, throttle body and the air intake. I have seen a lack of knowledge in this area end a few cars. How does the EGR fit into the mix. If you have negative pressure the fresh air intake to crankcase is plugged?
Kyle,your videos are great. Like how you breakdown and simplify everything. Thanks for taking the time to explain things. 👍👍👍
At the end of the following there's a point and lesson about a PCV valve:
I have a 2002 Toyota Sienna with 230,000 miles on that just lost its #5 cylinder ignition coil. Two of The front ones already went. But those and the spark plugs are easy to get to.
Well so with the rear coils and plugs when you have to take off that intake platinum. My mechanic is a friend who's retired from active mechanic work and now works out of his house at cut rates for friends, but it still cost enough.
So I Wasn't going to fool around with anything aftermarket. Back there, so I hadn't put OEM Denso coil packs in the rear. And I put OEM Denso iridium 100k mile plugs all around.
I got the car in 2012 with 136k on it and I just had him do the plugs back then with the NKG equivalent of the Denso iridiums. So those were fine. But I feel a little cheated because now they only had 65.5k on them. 😄
But also back in there the PCV valve, much less at it's grommet, Is not easy to get to.
oh, sure, everybody might have their little tricks to reach it and do the job. But that's if everything goes smooth. But in this case, even with the plenum off and full access, it did not.
For one thing, when I first got this car in 2012 and had him do the tune-up, I didn't even consider the PCV valve. That was a major F up...as it now seems that it was the ORIGINAL.
So, when my guy went to remove it, to pull it out of the grommet, It was so brittle it's snapped off flush with the grommet.
He then used his needle nose pliers to pinch a section of the PETRIFIED grommet and try to remove it from the whole in the intake manifold.
At which time 3/4 of it that was below hole broke off and drop down inside. Between us taking turns it took us nearly an hour to get it out of there. It was in one large chunk with no flaky pieces, and he pretty much suggested just leaving it in there because there was nowhere for it to go and it wasn't going to get sucked into anything as big as it was. But it's size and shape also prevented it us from getting it out through the hole with pliers or hooks. He finally got the idea to spear one end of it with a Instrument that look like a broken dental pick and rolled it up through out of the hole like that.
But the bottom line was
that PCV valve was pretty cruddy and I'm sure it was poorly functioning at best.
And I think that because of what I have since learned about What PCV valves do and how they work in relation to pressure in the engine.
When my mechanic pulled out my coils and my spark plugs from the back there was a little bit more oil on or around them than there should have been. Not awful, but time to think about a head gasket sometime in the future.
Well, I'm sure that's true in a car that old. But I'm also thinking that If that PCV valve was bad and the pressure had built up in the crankcase, that might have exacerbated any problem like that pushing out oil where it would not normally have escaped from and something like a head gasket job might not really be an imminent issue now that the valve is replaced. IDK. But maybe.
Also, and I don't know if this is a thing, but I seem to have a noticeable amount more giddy up and go with seemingly less effort. Again, don't know if that's the PCV valve ffully functioning or not over a clogged one. I doubt it's my coil packs and new spark plugs. Those either work are they don't?
Also, because my PCV valve in this car was hard to get to I went with a genuine Toyota OEM one from the stealership. Same with the grommet. I researched it online. And too many people made too many good points about aftermarket ones not necessarily being 100% calibrated specific uses in that they have to fit so many makes and models of cars. So yeah, for the peace of mind it offered me for such a very simple yet very important part, It was worth it.
Moral of the story (mini novel 😁):
1. Don't overlook the PCV valve.
2. Don't skimp on quality. ones or the right fitment.
3. Replace the grommet at the same time.
4. Do not waste time cleaning them INSTEAD OF replacing them. If you like only do it as a general maintenance thing to keep them unclogged. Like if it's easy to get to and you want to do it every other oil change or something like that. But the SPRINGS wear over time and lose the appropriate tension. So it can rattle and still be fucked up.
Best to all and thanks for this video.
I am hoping this is the fix for my 1985 Prelude which I was stupid not to start up for a year. It backfires now and revs shoot up on start up so having changed leads to plugs and coil and thinking this may be the cause...if I can locate it. I have a manual but although it recommends that it is replaced every 30k it doesn't show its location. Having watched this I should be able to locate it now. However getting a part for this car in the UK that is original manufacturers is near impossible...just seen someone selling a distributor cap for £100! Luckily I found a couple new in USA which were cheap so got my freind to buy and send over!
Excellent video Sir. Another thing that is taking place is at long idle times, the crank case pressures are also allowed to vent into the intake tube behind the throttle blade. That particular tube really serves two purposes. Great job with this video
Thanks a lot for a clear explanation. Now I learned at there is actually cleaned fresh air coming into the crankcase, and then there is a pcv valve which regulates the vacuum in the crankcase. I will rush to my Engine bay to see my own vacuum system.
Very informative and straight to the point sir! The illustration on the white board was perfectly executed as well! Oddly enough my engine does not use the traditional style pcv valve, it uses what seems to me like a flow restrictor and a smaller vaccum hose for this portion of the crankcase venting. The other portion which is a larger hose connects, How you described after the maf before the throttle plate. My engines valve cover only has one fitting that attaches to it and it’s basically a “T” adapter with two hose barns on the end. One for the larger fresh air hose and one smaller fitting that goes and connects under the intake manifold. I’ve been trying to install an oil catch can to minimize the amount of oil building up inside my intake manifold. I know my best option for maximum performance would be to vent all this to atmosphere which I have done in the past previously on the race track but if I’m daily driving the car it smells like crap and vapors are pretty strong since I do have a higher mileage performance engine that’s due for pistons and rings when I’m in a better financial state. When installing an oil catch can in line with my cars system it seems like I must install a can “in-line” with both the smaller and larger hoses ?
I would cause alot of damage if i deleted the smaller hose in my system that’s pulling the crank case fumes during idle eight ? I’m just trying to understand and be sure before I spend extra money. It sounds like I need to install two seperate catch can…..one for idle and vaccum state and the other for wide open throttle conditions 🤷🏼♂️
Yes I remember, I was a boy then and driving behind a vehicle I saw the tube spitting out the gasses on the road, it's interesting to be learning about it now after all those years.
I like guys like him... good talker, plain speaker, and lots of mechanical skill and common sense... PCVs are cheap and easy to replace by yourself and are simple to overlook!. Mine can be thoroughly cleaned with parts cleaner and replaced or a new one is a few dollars and easy to install on my 2000 Corolla....
It is amazing how cars work. PCV valve is a very important part that people almost never change. It is a part that goes silently Unnoticed!
Best explanation of the PCR I have seen on UA-cam.
Gotta say, this is the best damn explanation ive ever had the chance to be present for. No room for misinterpretaton whatsoever. I even had the spring actuation behavior straight nackwards in my mind for awhile now, thinking that vacuum was acting in the complete opposite direction. No wonder i was confused. Right on my bradda, myth busted! Mahalo!
Great video. I’ve been trying to make my car run better and this is one part I’ve overlooked for a long time because I thought the PCV valve didnt do much. I’m about to change the valve cover gasket which has been losing some oil lately, now that I know about the crankcase pressure thing I’ll do the PCV also.
Damn.
Explained and shown.
The cut-open pcv helps.
🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣
Great video! Clear and concise explanation with helpful illustration and demonstration. Thank you.
Started watching this after I replaced one in my Honda. Just shake it to see if it rattled. If not, replace it. I didn’t think it would make much of a difference, but it did. It doesn’t run Rich anymore and mpg shot up. Car runs great and it got its power back. Check it every oil change. It’s a$3 part that really helps.
Excellent teacher, good verbal skills and logic. Good details efficiently delivered.
Also what's important to note...the pcv valve hose always goes to manifold vacuum and the opposite side of the system goes to pre vacuum (air cleaner) before throttle body or carb. I've seen people do it wrong.
Very clear easy to understand explanation must have watched 10 vids on this subject and this is the only one that was detailed and I was understood completely...
thanks...
Awesome explanation man, thanks. I kept hearing a buzzing sound on my Silverado inside the engine bay on the driver's side. It was making me a little crazy. Turned out it was the check valve in the pcv. No big deal, just annoying.
Thank you. You did a great job of simply explaining the PCV system. I had a general understanding but this helped me a lot.
Hi Kyle I see that the direction of the PCV flow is from the air-box through the breather filter to the crank case, to the PCV valve and so on; what I'm trying to understand is how does oil end up in the air- box which is opposite to the flow, and why isn't the breather filter preventing it from going to the air-box?
thanks for the video.....i was having issues with my car and saw another video that mentioned the PCV system, i dug deeper and on my honda civic it was easier to change the PCV valve than it is to change gears....so i did it....the guy at the auto parts store said these should be changed once a year....but that seems a little exessive.
The most informative PCV video on the web. Thank you
great video! Love that you cut it open! Very clear concise explanation
The best explanation of how it works on UA-cam. Thank you.
Thanks everyone for checking out the video. If you liked this video, we have more videos on Emissions Control Systems and many other videos you might enjoy about the Automotive Industry.
after seeing a lot of diagrams and videos, this video has explained all I need to know. Thank you very much!!!
Thank you for this. I now understand how the PCV valve system creates positive ventilation. I was thinking of installing a catch can realise now I'd better do more research first.
Best explanation I've seen. The cutout PCV really solidifies understanding. I was only looking for a refresher since my classes were in the 90's, but got a really deep understanding of the system. Wish my teachers cared this much. Thanks for the effort.
Thanks finally a video that really explains how the valve actually work at idle and full throttle!
My Mx5 was spark-knocking and smoking like crazy- took it into a shop, they did a compression test and cleaned the fuel injectors and told me to run higher octane fuel, charged me $465 and didn't even solve the problem. I installed a new OEM PCV valve, and voila, corrected the problem, has never run better!
I thought I understood the PVC valve but after seeing this I was a little wrong. Thank You.
Good work explaining the system. Makes sense now.
Man so good. Thank you.
.. been battling a short term fuel trim issue.
Thank you so much! We replaced my pcv valve... old one was horrible looking, I noticed sludge on last oil change, terrible gas mileage, oil around my coil packs, leaking small amounts of oil under the engine... Anyway it all was a hot mess! So now we put the new pcv valve in and test drove - when I came home at an idle there's a loud rattling sound. Where should I go from here?
After all these years I've learned something thanks 🙏
Your video is a lot better than one I just saw on u tube !, that other video didn't even explain how the pcv valve works!!, also one question, all of the pcv valves I see these days either don't have anything in them but a small hole, or they have a small hole and a small stainless steel ball that rattles when you shake the valve, can't find any like the one you cut open ? Can you please send some information on where the spring controlled valve can be found? Thanks 😊
I really enjoyed the way you explain. And it is easy to process information, coming from a person that just started doing DIY stuff to enlarge vehicle lifespan. Great job!
I have subscribed because is the type of mechanical explanations I am looking for...thank you
Definitely in the top 2 videos I've seen about this.
Amazing and the best explanation of PCV operation. Thank you a lot Kyle.
Thanks excellent keep up with your great work 👌
Uta! con este hombre ni inglés necesito muy buena explicación gracias 🙏 que dios me lo bendiga mucho!
Great video!!! Liked and subscribed!! I always wondered the specific function of a pcv valve, I'm replacing mine but it gives me peace of mind to know that's most likely my issue based on the symptoms and everything else being replaced. Cheers!!
thank you for the video. i didn't understand the need for fresh air ventilation . why the PCV system can't perform just with air intake vacuum?
Great explanation on part throttle and closed throttle operation of the PVC. At WOT (wide open throttle) when there is least amount of vacuum, the spring pushes piston down onto opening effectively closing the PCV inlet. Its a neat little valve that works in 3 modes with only 2 moving parts.
i remember those tubes during the 60;s they ran down ; always wondered why my dad cleaned them from time to time < old cheavy 1962 straight 6 cylider , she was a truck and a tractor it seemed .. thanks awesome video ,,
This is the best explanation I have seen of the pcv valve. Thank you very much!!!
Hi Buddy (master educated man)
I watched many of videos,
But for me no one explains as U, especially circulation of fresh air pushing blow by air out,
The way after MAF sensor air circulating,
God blessed U Buddy
Amazing explanation, Amazing.
👍👍👍
Great video, not sure if I have a bad PCV valve on my new rebuilt 390 on my 68 cougar. Have oil leaks and off idle hesitation
Showing the inside of the valve was the best part 🔵🔵🔵👍👍👍😀😀😀🔵🔵🔵
Around 1960s, there was higher demand to control the smog. Therefore do not vent the the crankcase to outside, but to feed it into the intake. Problem 1, it was common to have engine back fire, or flame coming out of carburetor in the old day. Or tail pipe. If the flame enters the crankcase, it will pop the engine oil seals. Therefore the PCV, or an one-way check valve. Problem 2, the PCV has a dirty live and it can get clogged over time. You will notice it during high intake vacuum (low RPM or decelerate). Such as your engine will die when you decelerate around a corner. I am not sure if there is a modern high tech solution? But I have not seen PCV problem for over 15 years.
A little bit of preventative maintenance goes a long way to avoid serious, expensive repairs.
Even if you have no idling issues or other symptoms, it’s just a good idea to replace certain critical parts after a specific interval. I replaced my PCV valve at 120,000 miles while replacing the water pump and drive belt. Honda recommends those parts be serviced after 100k miles.
Excellent! Thank you very much very professional very informative.
It’s funny but every time I get an oil change I notice I have to put in about a quart within a months time after that seems crazy I just thought it was just burning oil because it was older.
Now after doing some investigation and research and I know I can take action myself.
So far I added some oil and a Lucas additive and it’s great. Then I clean the air intake valve and it works even better and now I will clean or replace this PCV valve. It seems crazy that this is the first time I think I’ve really heard of this.
7:25 it’s called a chamfer. Great video
THANK YOU. I finally understand how the PCV valve works.
first thing i'm going to check in the morning. thanks for all the great info. great job.
On my 2002 Ford Focus, although it uses a MAF sensor, the PCV breather intake is not metered and the value is simply programmed into the PCM. The hose connects before the MAF sensor.
TY for an excellent explanation of PCV system.
Great video when you use a long duration Cam does it need a different pcv for low vacuum at idle?
wow i have difficulty in learning that said i wish this guy could have been my teacher in school i would be a genus now thanks
I greatly appreciate that. Thank you, I'm glad you enjoyed the video.
Very well done. Thank you for this detailed pcv value demonstration.
Good clip thanks. My van runs rough at startup with check engine light coming on.Could that be bad PCV .
its first time I saw pcv funtion..... and it was easy and comprehensive.....