Oil in coolant tank

I had oil overflowing the coolant tank. What are the sources of oil into the coolant? I removed the oil cooler and checked the coolant side with a vacuum, it held 25 In Hg.

Thanks!

Look at the condition of the engine oil on the dipstick. If it looks milky or unlike the typical jet black pure oil, you might have a head gasket failure with coolant entering the oil and vice versa.

Sounds like a head gasket. I would do what Tom says and pull the dip stick. You may have gotten lucky and the oil only went into the coolant. Just see if the oil looks white/ milky. If its only in the coolant I'd say that's the luckier symptom to have.

Oil to coolant only

Oil to coolant only. Oil was 1.5 quarts low. This car uses 1 quart at 10k. Not near that at this failure. So the head is coming off now!

Thanks

Oil pressure >> coolant pressure, so not uncommon to only see oil in the coolant as the result of a headgasket breach.

Could also be a head or possibly oil cooler. Never seen either fail that way on a BHW though.

I had put a vacuum on the coolant side of the oil cooler. No drop in vacuume. I put 65 psig on the coolant side and under water, NO bubbles. SO I changed the head gasket. ALL looked good, no warping. All flat. Put it back together, still getting oil in the coolant. No coolant in the oil. So today I bypassed the coolant lines to the oil cooler. With open coolant connections on the oil cooler, engine running, cooler is leaking it is a Nissens, replaced 4 years ago... Is any aftermarket good??? VW is expensive and not sure who makes it.

Nissens can be hit or miss quality wise, usually most of their stuff is reasonably good, as good as a lot of things that are not OEM.

Regarding the BHW's oil cooler: the part number has been updated numerous times, starting with a B suffix, then C, D, and finally E. The E suffix is the same one used on the CBEA/CJAA CR engines. 038-117-021-E and I have found the one we get from Worldpac to be identical to the OEM one. They were Febi branded, but that means very little. Mahle, KTM, Modine, Mann+Hummel, and others are some of the OEM suppliers, but I do not recall an actual name being on these particular coolers.

I think I know the answer, but can someone explain why it couldn't be the EGR cooler?

Because there is no engine oil passing through the EGR cooler.

Got a good used VW oil cooler from a 2007 V6 Touareg from LKQ for $15, cleaned and flushed. Working great!

Yay! Congrats. And thanks for letting us know.

Cheers,

PH

For those who never once thought about the oil cooler, like me, here is a very long but helpful thread about them, with pics.


http://forums.tdiclub.com/showthread...+cooler+passat



Does it warm something up? Or cool something down? Or do both at different times?

It is technically a "heat exchanger", so it will work to equalize any difference in the two liquids (or gasses, or whatever). In the case of these oil coolers, they actually work to warm the oil early on, as the coolant starts to warm up quicker than the oil does, and cold oil is not good for the engine. You actually want the oil pretty close to the point of boiling water to insure any leftoever water vapor from the combustion process floating about inside the crankcase gets reliably turned to gas so as not to sludge up the insides. Diesels are not bad about this, however, since they do not have nearly as much water vapor inside anyway as they are burning much less fuel.