# Oil in Coolant Reservoir



## g_spud (Jan 2, 2010)

Hi All,
I recently purchased a 2000 vw v6 30v passat and noticed that it was starting to overheat and there was oil in the coolant. I understand that this could be a head gasket, cracked head or cylinder wall, but I was hoping that maybe there is something else that is typical only to VW such as a leaking oil cooler (I'm not sure if this car even has one).
I believe the cause for the overheating was a faulty thermostat as the temperature gauge and heater were not working correctly plus the secondary electric cooling fan wasn't kicking on. I'm thinking the relay wasn't getting the correct signal as the thermostat was closed.
At this stage I am not seeing any oil on the dipstick but I also understand that water floats and the dipstick reaches down into the sump.
Any comment would be greatly appreciated.
Thank you.


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## tryin2vw (Dec 30, 2006)

*Re: Oil in Coolant Reservoir (g_spud)*

Usually this is the oil cooler. It is located between the oil filter and the engine block.


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## Old Rabbit Dr. (Aug 18, 2006)

*Re: Oil in Coolant Reservoir (tryin2vw)*


_Quote, originally posted by *tryin2vw* »_Usually this is the oil cooler. It is located between the oil filter and the engine block.

I agree.
A leak down test on the cylinders (compression) will tell if it may be head gasket.


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## O_o (Nov 12, 2009)

*Re: Oil in Coolant Reservoir (g_spud)*

1. X3 on it possibly being the oil cooler. It might also be the intake manifold gasket, but I think that's less likely.
2. Oil floats in water (and eth. glycol). If your dipstick is clean and dry, then your oil level is low. If you top it up and it's foamy on the stick after running for a while, that would be a strong indication that the head gasket is the culprit. Either way, a leak-down is a good idea.
3. The thermostat doesn't do anything except open and close. So, if it is stuck closed, the engine would overheat, but the temperature gage would still display the correct temperature and the fan would still do its thing. Those not working suggest the ECT sensor is faulty.


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