It may not be a oil cooler leak - W204 V6 OM642 C-Class Mercedes.
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- Опубліковано 26 січ 2023
- You might think you have a oil cooler leak on your Mercedes W204 OM642 diesel engine but it might not be, before you payout a very expensive repair bill to replace oil cooler seals there is one thing definitely worth checking....
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Great video. I had a dripping leak and mechanic diagnosed oil cooler seals even without properly checking the car. I gave this a shot and to my surprise the inlet seal wasnt even clamped on, completely loose and the PCV valve seal wasnt even connected. I had my car for service a couple months back where the dpf was serviced and air filters where changed. Im guessing they forgot to put everything back.
Fantastic outcome as you can only imagine the price of the oil cooler seals having to be replaced..... mrix
Remember to replace both seals. The turbo inlet and PCV seal when replacing the air intakes Y.
Also if there is a lot of oil in the turbo, it is worth replacing the PCV value. Not a huge job, you will need a few small tools to get the DPF differential pressure sensor mount off and out of the way.
Hi, I have replaced the PCV valve with a brand New genuine part and another one from another brand and it never helped at all, the PCV I am sure can no longer cope with older engines and the extra blow by and that`s why many tend to opt for a catch can, however so far so good this end.... mrix
@@mrix that’s unfortunate, some oil blow by is expected but not huge amounts if you are not dumping the throttle.
Quick opening and closing of the throttle, does tend to suck up oil from the crankcase
This is very interesting, and I applaud you for putting out this video. I have an r350cdi with what I suspect to be an oil cooler seal leak. The oil cooler seals were replaced 5 years ago, and car was not leaking oil when I purchased it 3 years ago, but it does now... been bracing myself for the financial impact or pain in the backside of having to replace the oil cooler seals. Will try this out first, as you say no harm in checking as it is a far simpler, cheaper and more DIY'able job to do. Will try eliminating any potential leaks from this intake to turbo seal first. Thank you, subscribed!
All the very best of luck, I once again have another oil leak and its highly likely down to the turbo seal but I will be doing another video shortly if it ever stops raining here! The trouble with these engines it appears when they get older they tend to produce more crankcase oil vapor and the pcv valve and the seal simply cannot cope with it, many say its a design floor, when the engine it New there is not so much blow back which you get on older engines.
Anyway I have already replaced by turbo seal 4 times and also replaced by PCV valve which made no difference. anyway your certainly doing the right thing by checking that seal first... all the very best....mrix
@mrix I was thinking of doing PCV valve same time as I do the turbo and pcv breather pipe seals. If that doesn't 'work' then perhaps an oil catch can is the way to go. On my old cupra R I've deleted the pcv system and replaced with an oil catch can. That has run flawlessly for 5 years now. The 4pot 1.8t was easier to work on and car cost less so I wasn't too bothered about 'havin' a go'. I've been more reluctant with the merc as it's a bigger more complex motor and you think to yourself surely Merc engineers would have done a better job than something you and I can plumb together ourselves on the drive... but perhaps PCV and EGRs etc are really just not worth having when these vehicles get older... they are after all fitted mainly for meeting emissions regulations, though I don't want to downplay the environmental impact of our big old diesel engine cars. Maybe, just maybe, we should be deleting the PCV and putting in catch cans instead...
I also went down the route of a catch can and watched so many UA-cam videos on how to fit one unfortunately for me it all went pear shaped! it was fairly easy to do but for me it cause no end of blowing smoke from the exhaust, not sure why it happened but for me personally I decided not to try it again, regarding the pcv valve many videos tend to to put across and say the valve seal is warn because the seal hole looks much larger that the brand new version but this is what happens just after a few hours of use as the heat forms it in that way, as I say I purchase a Genuine Mercedes PCV Valve and it made no difference at all... all the very best and please let me know how you get on as I am now curious....mrix
Had my oil cooler seals replaced and new Egr, cpr, new dpf and oil level keeps dropping
Had my oil cooler seals replaced and new Egr, cpr, new dpf and oil level keeps dropping
Going to try it hope your right mate, 2014 E300 leaking seems very similar to what you're saying. Fingers crossed it's the same 😮
All the very best of luck, if you do notice oil just outside the turbo you will need to get yourself a new orange seal, also be very careful lifting the filters away as they can easily break, as you can see in the video the maff sensor can compress a fair bit first and then you can lift away from the air filter.
If you do happen to see oil that has dripped down through the orange seal its obviously going to take a fair while after being fixed to stop dripping as its likely covered a fair amount of the engine.
Anyway I would be very interested to hear if you do go through this process please let me know if you do notice any oil dripping through. thanks mrix
that is a completely normal amount of oil, naturally a little gets past the turbo seals, there's no way that would create an oil leak at the bottom of the engine
Hello Dean, that amount of oil can accumulate in just a few days if the seal has failed, where do you think that amount of oil is going ? there is nowhere for it to go apart from eventually draining out the bottom of the engine ? when a garage sees a oil leak from the bottom of the engine even if its a small leak they assume it must be the oil cooler but in many cases I simply believe it to be the turbo inlet seal failed... technically there should be no leaking from that orange seal at all so this video is a valid warning to at least check the turbo seal before going further and spending a small fortune on the much bigger job of replacing the oil cooler seals.......mrix
Having worked on this engine for years, I can confirm that this is a significant cause of oil leaks in the OM642. The biggest risk of that particular leak is that it tends to run down onto the swirl flap servo and eventually break that. It also creates an oily mess which can damage belts and other things. The 2 ways to address are (i) to replace that seal every few years as part of regular maintenance, and (ii) add an oil catch can between the pcv valve assembly and the MAF assembly (that large black plastic intake part that connects the air filters to the turbo). There are lots of videos on how to add an oil catch can there, and it's a very common upgrade (especially in the Sprinter community). I found that a 350-500ml catch can is not large enough and required dumping between oil changes. 750ml seems to be the right size for the amount of blowby on my 200k+ om642. The catch can has at least 2 critical advantages. First, it eliminates (or greatly reduces) the oily vapor getting injected into the MAF assembly and the turbo. Second, given that this is a direct injection engine, it reduces the amount of oily vapor and carbon getting injected behind the valves, which significantly build up over time, restrict air flow, and require walnut blasting (a job similar in scope to the oil seal replacement).
Hi Lewis, thanks for the input, very interesting..... mrix
Hi mate, wondering if youd be willing to give me some advice on common issues with these if I were in the market to buy a used one? Probably looking at 2010-2013 E350 CDi's. What would signs of the oil cooler leak be or is it going to hard to assess when viewing? Is there any other issues I should look out for? Cheers!
I sold it and i got the problem solved... this engine is garbage waste of money and time no access to work, everything needs to be programed etc
Good job, excellent presentation of detail views for each step. I basically have the same engine style but in a 2008 Jeep Grand Cherokee with a 3.0 Mercedes diesel and to stop this condition of oil being drawn into the turbo I have installed a "Oil Catch Can system" basically a container holding a replaceable filter, between the turbo and I believe it is call the EGR valve (mounted on top of passenger side valve cover). Since installation this has worked well, collecting vapor oil in a separate container which is dumped regularly. But I still worry about those Oil cooler seals. And to keep those pliable an additive to the oil (added once in two years apparently) from NAPA has been added which is suppose to work on the seals of the engine to keep them pliable. Not sure if it is working but so far so good. Wish you well from Canada, Mb.
Thank you so much for the in depth reply very much appreciated good sir, I have tried a catch can but for whatever reason it never worked for me, I had a strange situation whereby the blow by was not able to escape even though inlet and outlet pipes appeared fine ? what catch can did you use ? thanks and best regards....mrix
ProVent 200 is the make of Catch Can I have continued success with, all the best. @@mrix
Also should have mentioned that the EGR unit needs to be changed regularly but with a good quality unit. The internal diapham seem to warp over time. @@mrix
Thanks for that feedback, much appreciated.
I have never changed or replaced the EGR Valve as its meant to give off a error when there is a problem ? do you think they still require replacing ? and do you think it does affect the blow by or adds in some way to that issue ? thanks again....mrix
I'm getting oil there but also oil going down all over the serpentine/fan belt at the front of the engine.
When the car gets older it does tend to leak more oil from the turbo inlet due to general wear and tear of the engine like piston rings blow by, I dont suspect the oil could make its way to the front of the engine from that point ? I suppose its possible if it gets picked up from the lowest point of the belt ? anyway when / if you find out please come back and let us know..... all the best sorting the leak.....mrix
Started leaking for 7 months now. The engine oil level was about half way. Noticing drips at work. Will check this but the car does have 210,000 miles so could be either. Is the seal that's damaged the one with jubilee clip?
Hello I think in all of these cases its worthwhile taking a look as the turbo seal on a older vehicle does not hold up, I changed mine 4 times already..... all the very best of luck with a less costly outcome...... mrix
Hi mate, great video but have you got the part number? Thanks
Hello, yes its A6420940180 all the best doing yours...mrix
Thank you mate! Appreciate the quick reply
Hi, would this apply to an E-class engine as well? I'm being told that the oil cooler needs replacing. The car went in for service, oil change etc, and after about 4 weeks oil leak developed. I'm not a mechanic so the question might be doh!
If your e-class has the OM642 engine then yes it maybe the same problem.
Thanks for your reply. I'm pretty sure it is as it 2010 350 v6 Bluetec@@mrix