Oil in coolant

2001 VOLKSWAGEN PASSAT
118,000 MILES • 4 CYL • AUTOMATIC
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BOBBYWYATT86
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2001 Passat. Check engine light came on. Autozone's free check found an O2 sensor went bad. Upon having that fixed, my mechanic-friend noticed oil residue in my coolant tank. I have since heard a few theories about the root of it: the head gasket, a seal broken on a washer, and the oil cooler. My actual mechanic believes the oil cooler to be the problem. Who is right? And should I get a new reservoir and hoses put in, like someone else I know, or would that not really help at all?
Feb 2, 2011 at 12:38 AM
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JACOBANDNICKOLAS
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First, you need to determine if it is engine oil or transmission fluid. If it is motor oil, have a compression test done to see if there are any low cylinders. Also, check the transmission fluid to make sure no coolant is getting into the transmission.
Apr 4, 2011 at 11:39 AM