Engine "Squeak"

Post by **matthuger** » 21 Nov 2011, 20:51

My '05 S40 recently developed an irregular squeak that is occasionally noticeable (especially while idling). It seems to be coming from the general area of the head (or cylinder...it's a bit hard to tell) nearer to the driver side (as opposed to the timing belt or other belts). I'm worried it could be a bad bearing on one of the cams or a bad valve lifter or something...but one thing that confuses me...while idling, if I remove the oil cap from the head, there is a good amount of vacuum. Once the air is done rushing in through the opening, the squeak stops and when I replace the cap, the squeak starts again. Why would the head be under vacuum? I thought the PCV only ventilated the crank case. Could I have a PCV issue? Perhaps the gas mileage is a bit worse than normal but I haven't noticed any other issues. Any thoughts?

Post by **Choguy03** » 21 Nov 2011, 22:01

That is interesting. Are you seeing smoke come from the dip stick tube when you remove the dip stick? That is a sure fire way to check if the PCV system is clogged. Not sure about the squeaking, bit this looks like a place to start.

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Post by **jimmy57** » 21 Nov 2011, 22:54

Consult a dealer to see if your car is in a campaign VIN range for the crankcase pressure regulator replacement. That is part of the crankcase vent system (PCV system). The noise you are hearing is common when the CPR fails and lets the crankcase go into vacuum and pulls air through cam or other seals. The noise is the whistle of air past seal and should stop if the dipstick is pulled if that is the cause.