TimC300

My M272 just hit 150k so im going through everything to address any issues. i noticed oily gunk on the intake manifold below the fuel rail and on the front of the manifold and also on the rear around the throttle body. I just bought and replaced the oil separator drip pan and the crankcase breather cover, sure enough there is oil in the breather hose. I plan on removing the mass air flow sensor and elbow below it to clean up any residual oil. The old breather cover gasket was completely flattened but surprisingly did not appear to be leaking, but there was clearly oil inside the cover where the hose is attached. The drip pan actually looked good in my opinion, some wear on the shaft where the cover fits on to but no grooves. I was even debating whether to even replace it but then I noticed oil inside the drip pan where im thinking there shouldnt be. On the opposite valve cover the air oil separator gasket looks fine, zero oil leaking. My question is how does that air oil separator function, ive read there may be a valve or flap that can get stuck open and allows oil into the throttle body. How does that side even function, does air get drawn from the crankcase or does air go in to the crankcase from that air oil separator? I can kind of picture how the oil separator drip pan functions, looks like it spins and the oil gets flung to the outside and should drip back out instead of being allowed through the hose. And why not the same setup on both sides, why does the passanger have the drip pan and cover and the drivers has that box looking air oil separator? ive searched around to learn but not finding exactly the info i want to learn from. i did read they are different due to one working at idle and the other working at full throttle?


old breather cover. gasket is flattened. The round seal actually seemed tight when i fit the old dip pan in it, def was not loose. but theres oil in it so replaced. I bought the Febi brand from FCP.


Old drip pan. Shaft looks fine to me. For 150k I was expecting deep grooves. Maybe it has been replaced at some point.


I will say replacement was so much easier than I anticipated. I research everything before I start the work and heard horror stories about reaching the bolts. The cover bolts on mine are E10 and obviously my socket wouldnt fit back there. I have a regular 8mm box wrench I used for 3 of the bolts which worked great, just had to crack the bolts loose then they spin off by hand. For the bottom bolt nearest the battery i bought a 5/16 offset box wrench, actually the ProGrade 11250 1/4 X 5/16IN OFFSET DOUBLE BOX END WRENCH. Was $5.45 and i think it saved me alot of aggravation.




For the drip pan it was an E8 socket, I used my 1/4 small ratchet with a 1/4 universal joint as an extension and it fit perfectly. Deep enough to reach the bolt but just short enough to fit the ratchet in there. Reverse thread so make sure the ratchet is set properly.



I did drop a bolt one time but thankfully I removed the plastic undertray for some upcoming transmission work so the bolt fell right to the ground and was easy to find. I was thinking maybe its a good idea to shove a towel down in there to catch the bolt if you do happen to drop it so it doesn't get lost. There was a large ground wire that runs right over the cover and it was zip tied to the hose part of the cover i had to snip, then unclipped the wire near the throttle body and pushed it out of the way to get the cover off. Took me about an hour and i took my time, cleaned everything while I was in there. Drives me nuts watching video of people doing work and the engines filthy.