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Q: Air filter housing

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When I was changing air filter I noticed, what seems to be oil in the air filter housing. My car has been running sluggish lately. Recently the engine temp light came on but my mechanic said he didn't find a problem. Also the a/c doesn't seem to be very cool. What could possibly cause oil in air filter housing?

My car has 160000 miles.
My car has an automatic transmission.

If you are getting oil in the air filter housing, this is from the vapor line coming from your crankcase ventilation. The oil can be from a PCV valve that is clogged and in need of replacement. The valve relieves the crankcase pressure when the engine is running and cannot do this if it is clogged. Check and replace the PCV valve first, then see if the problem still happens. If it does, then the engine may have a piston ring leakage problem that would require an engine rebuild and replace the piston rings. To have this looked at in person, a certified technician, such as one from YourMechanic, can come to your home or office to inspect the system for oil leaks and let you know what repairs are necessary.

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