tedcorm

Sorry if this is poor etiquette, but I already posted this in the c-class forum and getting no response. I was hoping someone here might be able to help:

My c300 has a high pitched squeal when warmed up. Seems to decrease upon acceleration. If I remove the oil fill cap, the squeal stops, but there is a high amount of vacuum trying to remove the oil cap. Also, I noticed some oil in the air filter box. I can't seem to find the centrifuge? There seems to be more about this on the web for 2013 and prior vehicles. I believe my motor is a M276. Is that correct? Thanks in advance. Check engine is on - P0507 and (2) P2279 codes show.

chassis

Vacuum leak? Possible intake manifold leak somewhere? Check all hoses and valves connected to the intake system. The M276 is a pretty robust engine. I haven't read about the symptom you are having.

If the sound goes away with acceleration, it implies the sound is dependent on vacuum. The oil cap test is interesting and also suggests something wrong with vacuum (intake).

Ideas:
- loose or cracked hose
- loose or failed valve (PCV type valve)
- leaking intake manifold gasket
- cracked intake manifold

Redneckgator434

I have same problem on same car. From info I could gather it is the crankcase ventilation valve (centrifuge). It is located on rear pass. Valve cover. I was quoted 3+days and $2800.00. Seems high? Anybody else have any experience with this situation?

stevemos

Same issue here. Changed idler pulley, tensioner. Bought a shorter belt to bypass the AC - thought the AC clutch was squealing. Remove the oil cap and squeek goes away. Crazy vacuum on there.

Is the repair just the centrifuge cover OR both the cover and centrifuge? (All I see are people replacing the cover and gasket.)

Thank You!

Redneckgator434

Sorry to hear that you are having the same problem. I changed both the cover and the oil separator along with the (6) green intake gaskets and high pressure fuel pump seal and new bolts for fuel pump (.99c). I did not have much luck finding any info/ service manuals for this ear/model. one MB dealer tried to sell me the owners manual as a repair manual for $100.00. Called another MB dealer and while they couldn't send me copies of needed pages from factory digital service manual, they did offer to make copies if I would come by and pick them up is person. These covered the whole job part location, helpful tips (replace pump bolts), parts that needed to be removed for access, torque specs, pictures. I was truly surprised and blessed by this info. Job is fairly straight forward. Plastic electrical clips are very fragile. Removing fuelpump and centrifuge assm. are a PITA. No room. Make sure to have internal/external torx sockets/wrenches. (the new wrenches that look like trans.splines work great. FCP Euro is good place for parts.