Hello everyone, I have a 2013 C250 and sometimes the vehicle can have a rough idle mainly when the engine is cold but it can be random. And all l've really noticed is also on a cold start up the vehicle will blow some black smoke for 5 seconds, and when I take the oil cap off there is a ton of pressure pushing out the oil cap. When driving the vehicle I've noticed almost no issues with it. The vehicle has no codes so l'm kinda lost. All I can think of is an issue with the breathing system and crankcase breather valve but I'm not sure. Thank you

 

Have you actually used a code scanner yet? Because there can be codes that don't trigger a check engine light is what I've learned.

 

Yes I've scanned it, and I also had a shop scan it too and there are no codes stored

 

For the rough running on cold start up there could be different reasons. But for the smoke there is actually an updated banjo bolt for the turbo oil feed line. Of course the oil feed line has to come off so replace the o-ring, banjo bolt and 2 crush washers. These engines actually get a big leak from the o-ring on this line.

 

I'll check the banjo bolt, but I did notice a oil leak around the valve cover. I eventually found oil in one of the spark plugs and coils. Not sure why I never got a check engine for it. I will also be doing an inspection of the cam adjusters while the valve cover is off, if any one knows a quick way to diagnose them

 

Of course, Valve cover gaskets leak just like any other gasket. Highly recommend to use oem gaskets..

 

Okay so new development. I decided to run codes one more time because I was gonna clear the codes i developed from looking at the PCV system. Even though the check engine isn't on I now have the stored code: p001762

 

My C250 has the same code. It is sputtering RPM's at startup, and the accelerator is very jumpy. Does yours also act like it's almost going to stall while idling at startup?

 

I haven't really noticed anything recently but the rpm did jump a little and I've never noticed anything wrong when accelerating. But my father recently had an f150 with bad cam phasers and I really don't want to deal with another vehicle giving codes for the cams

 

You may wanna take a look at this thread if you havent done so already. Cant recall whether your code had anything to do with the cam phasers
https://mbworld.org/forums/c-class-w204/799221-extended-warranty-camshaft-adjusters.html