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So having a bunch of oil leaks and engine's running a bit rough at idle on my wife's 2012 Mercedes C250 1.8l turbo engine (M271). I'm heard that a clogged breather system can cause these issues. I haven't replaced anything related to the breather system and the car has about 150,000kms. I took a video and there is a lot of pressure/blowby when I remove the oil cap.
What's involved in replacing the breather valve or whatever may need replacing in the breather system? I haven't been able to find any good videos/descriptions of what's required to get to the breather hoses. Some mention removing the air intake box and intake manifold (ie .a lot of work). Others say you can get to it from below the engine.
This is the only post I see that's not the same engine but looks similar.
I dont have that engine so not really sure what issue youre describing. When I search "Mercedes M271 breather hose" I come up with tons of information.
Finally getting around to replacing the crankcase breather on my wife's 2012 Mercedes C250 1.8l turbo M271.860 engine. Wasn't too bad removing the airbox, air intake manifold and the throttle body. I'm going to post a few pictures here to help others understand what's under the air intake manifold on the M271.860 engine. All this to replace the crankcase breather tubing which should help with oil leaks and stop gasoline vapour getting into the oil.
Before airbox removal Air intake manifold Throttle body After air intake manifold removal Oil in the air intake tube Bottom of air intake manifold Crankcase breather
Finally getting around to replacing the crankcase breather on my wife's 2012 Mercedes C250 1.8l turbo M271.860 engine. Wasn't too bad removing the airbox, air intake manifold and the throttle body. I'm going to post a few pictures here to help others understand what's under the air intake manifold on the M271.860 engine. All this to replace the crankcase breather tubing which should help with oil leaks and stop gasoline vapour getting into the oil.
Thanks for the pictures. I have been replacing the oil filter housing on the 2013 C250. I disassembled everything several weeks ago, had to order replacements for some broken parts, ended up distracted on other projects, and will need to go back and finish the job. I took pictures of all the electrical connectors I disconnected but these pictures will definitely help.
Finally getting around to replacing the crankcase breather on my wife's 2012 Mercedes C250 1.8l turbo M271.860 engine. Wasn't too bad removing the airbox, air intake manifold and the throttle body. I'm going to post a few pictures here to help others understand what's under the air intake manifold on the M271.860 engine. All this to replace the crankcase breather tubing which should help with oil leaks and stop gasoline vapour getting into the oil.
Before airbox removal Air intake manifold Throttle body After air intake manifold removal Oil in the air intake tube Bottom of air intake manifold Crankcase breather
I replaced the PCV and check valve hoses as you did and I’m still having blow by through the oil cap. Did this solve your problem?
Finished the job. Car runs great but still have the blow-by. Not sure if there's anything wrong or that's just the way it is meant to be on these cars.
Finished the job. Car runs great but still have the blow-by. Not sure if there's anything wrong or that's just the way it is meant to be on these cars.
I have the same issue as you now. Replaced the low pressure PCV (under the intake manifold) there is a high pressure PCV built into the valve cover. My other thread has all the info on it.
I am waiting on a new valve cover to swap it and see if that fixes the crankcase pressure at idle. Will report back.
Every now and then a dumb question.........................
What would be the average odometer reading when the C250 coupe breather issue surfaces?
(I have a C250 coupe - which my new wife loves)
Thanks
ez
I’ve seen cars with the m271evo engine have this issue at 57k , 80k, and mine happened around 95k miles.
it is likely due to lack of maintenance and or lots of idling. I would just keep an eye on it and monitor the blow by. Once your oil fill cap no longer is sucked it and is hopping and jumping around, I would say a new valve cover is needed.
I’ve seen cars with the m271evo engine have this issue at 57k , 80k, and mine happened around 95k miles.
it is likely due to lack of maintenance and or lots of idling. I would just keep an eye on it and monitor the blow by. Once your oil fill cap no longer is sucked it and is hopping and jumping around, I would say a new valve cover is needed.
Ant
Like Ant pointed out, it depends on maintenance and type of use. I have 220K on my 2013 C250 with the original valve cover, but the majority of this is highway miles where I suspect the carbon or gunk does not have a chance to accumulate.
Like Ant pointed out, it depends on maintenance and type of use. I have 220K on my 2013 C250 with the original valve cover, but the majority of this is highway miles where I suspect the carbon or gunk does not have a chance to accumulate.
Thanks for the feedback guys. - I think 220,000 kilometer is close to 140,000 miles - and my wife's C250 coupe its about 44,000 miles. Looks good.
Finished the job. Car runs great but still have the blow-by. Not sure if there's anything wrong or that's just the way it is meant to be on these cars.
Richard
did that also help the gas into oil problems along with oil/gas residue in intake tube?
11-26-2023, 12:32 PM
