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This past weekend when I was changing my oil, I checked my radiator coolant. I noticed some oil floating in the radiator and on the underside of the cap. Also, the coolant overflow tank was down. I checked the oil which just came out of the car; no coollant in it.

I've had my UIM and LIM replaced 30k ago. I noticed a little leaking around the coolant bypass elbow. I do not run DEX. The car has 178k. Do you think this is terminal? I'm not too inclined to open the engine up again.

Thanks for any input of where the oil could be getting in the coolant.

What are you running? The old green stuff, or the mixes with any color? Was the system flushed out well when the coolant was changed? It could be left over Dex, sludge. Otherwise, you could be leaking transmission fluid into the system from the cooler in the radiator.

Which brand of UIM did you use? You can get coolant in your oil through ingesting it in the intake, and it leaking past the rings.

Is this on your car listed, the 99 SSEi, or another car? I just want to make sure we're diagnosing the right set of problems.

Bill, he also stated he did not have coolant in his oil, but oil in his coolant.

The only place that I know where oil can cross to coolant would be the the oil coolers in the radiator. It could also be transmission oil. How does the transmission fluid look?

Guys

Thanks for the quick replies. First, it is a '99 SSEi, I use Prestone and I do no know what brand gaskets used. An old friend chaged them and he's out of business now. I'll check the ATF this weekend. Should I check the trans dipstick for coolant? How can I tell if the stuff in the radiator is ATF? It sure looked like oil, not red but oild brown.

Thanks

I can relate somewhat after having oil in my coolant in one of my GM 3800 II's. What most sources indicated to me is that it is a head gasket issue. However, the consensus is that while it may not be pretty, the challenge was that oil will float to the top of the coolant making it look much worse than it is and that oil in the coolant isn't a problem. Coolant in the oil, would be a serious issue but apparently not the other direction. Given the cost of taking the engine apart to determine what the problem was I've decided to leave it for now and with about 15,000 miles on it I haven't seen much of an issue though I suspect that the coolant fan needing replacement might have related to that. (Light oil softening the plastic part to the point of failure?). So my guess might be "Valve cover gasket leak".

I checked the ATF and nothing seemed wrong. A little on brown side but it needs to be changed anyway.