[marktan]

Tracking down an oil consumption, plug fouling, and misfire issue has led me to remove the pressure valve that diverts the crank case ventilation from the driver side oil separator to either the right manifold (partial load) or the charge air intake (full load).

I discovered the diaphram inside the valve is completely disintegrated.

Upon further investigation, it looks like the seal ring that surrounds the camshaft in the housing may be not sealing.
My question:
Does the valve cover have to come completely off to remove the seal ring, or can I pull it out from the front?

Part numbers in question are:
seal ring: 2759970346
Diverter valve: 2750100291
(parts labeled 455 and 460 in the exploded diagram here:
CYLINDER HEAD. Fits: Mercedes | Mercedes-Benz of South Atlanta

Thanks!

 

[eric242340]

If I remember correctly it simply comes out from the front.

 

[marktan]

I replaced the pressure diverter valve and the oil seal ring tonight. What's amazing to me is that even "sick" this is a fast car. I just didn't know how sick she was until I finished this...What a difference it made with throttle response and overall power, especially at WOT; like totally different vehicle! Obviously having the crank case ventilation not being routed properly to/from the manifold and/or charge intake was robbing her of HP. Took about 30 minutes to swap everything out. The old seal took a bit of effort to pull out, but the new one slid in nice and snug with some gentle coaxing. I'm assuming the PCV vacuum leak into the charge intake or the manifold was confusing the pressure sensors. I did notice that my long term fuel trim was running rich, but with no apparent cause. I'm going to monitor it to see if it adjusts down with this repair.

If any of you M275 engine guys are thinking you're missing some juice AND/OR getting misfires that can't be tracked down (and you've ruled out the usual suspects like the coil packs), take a look at that valve. It didn't throw any codes on the MIL or through DAS/Xentry until it misfired, and then it just showed the typical P03XX codes. My coil packs are less than a year old and I had just replaced the spark plugs a few weeks ago, so I knew that wasn't the cause.
It was pure happenstance that I noticed a little oil seeping out down the front of the valve cover that made me think to remove the valve, which led me to notice the disintegrated diaphragm inside, as well as the poor condition of the oil seal ring.

 

[tony1963]

I prefer the V8 or an old Volvo. Thanks.

 

[haoz129]

PCV on Volvo is harder to maintain which is buried under the intake.

I have both the V12 and Volvo inline 5 turbo, they are different, love them all.