babyhuey6810

I have a 99 venture that has been a pretty good van.Has had the normal venture probs[power window,intake gasket,oil pan gasket],but its been ok.Six months ago I decided to flush cooling system to get dex crud out.Afterwards I had oily water and watery oil,so I replaced the intake gasket{twice,now has nice fel pro metal with revised bolts},put on new heads and gaskets.Still had water and oil mix so pulled off oil cooler.Low and behold,it bubbled under air pressure.I guess I should have done more diagnoses before rebuilding the upper end of the engine,but after seeing the damage dex cool does to gaskets I am glad I did the work.My question is has anybody had the oil cooler failure or am I the only one?Thanks.

LMP

THis occurrence has been reported on this or parent forums (Transport/montana/APV) a few times so the answer is yes. Oil (engine or tansmission) in coolant has been traced to blown oil coolers in the radiator in several cases: some models have an engine oil cooler on one side, transmission oil cooler on the other side; some models have only the transmissioncooler, sometimes using both sides.

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Wardrivr

Don't feel too bad, I did basically the same thing. I had the oil cooler fail on my '02 Silhouette. The first symptom was my wife mentioned the low oil light came on. Like you, I jumped on the IMGs since I had experience with it before with my '99 Olds. When I got to the point of hooking up the cooling system, I filled the radiator with plain water, let it sit overnight and in the morning there was a bunch of water in the crankcase. I started to suspect the heads, but then I thought about the other symptoms. When the engine was running the oil pressure is higher than the cooling system's pressure so the oil went into the cooling system. When the engine was shut off the oil pressure was zero so the cooling system pushed oil & water back into the crankcase. So I realized this can't be a head problem because oil doesn't flow through the head under pressure. Thinking of where else the cooling & lubrication systems could leak to each other led me to the oil cooler. It's just as well that I changed out the IMGs since they would have failed eventually anyway. I used the good Felpro ones.