It looks like there's oil sitting on top of the coolant in my overflow tank. Not much, maybe a 1/8 inch thick but this still worries me. The shop had just made a repair to the radiator for leaking coolant. they tightened the transmission coolant line and added stop leak. that fixed the leak at least. but now this?
Is it possible that this layer is just stop leak coming to surface? Please don't tell me this is a head gasket! That's the only answer I've found so far on the web is that oil in the coolant means a head gasket is bad
It drives fine, no over heating. heat works fine. temp is at the right place. oil pressure seems normal while driving. What can this be? Your answers are much appreciated!

 

I would check the overflow daily for any increase in the oil level in it. Also check that your oil isn't milky.

 

Oil doesn't appear milky. It does look a little full though. When I changed the oil about 3000 miles ago I filled it a little too much. But it had apparently no ill effects other than it dripped oil for about a week and stopped (I chalked that up as my adding too much oil to it). I am using synthetic oil if that makes any difference?

EDIT: Oil definitely doesn't look milky. I just went out and checked. Transmission oil is not milky or discolored either. I forgot to mention that the engine had been pressure tested maybe 2 weeks ago and showed no leaks. the shop told me that ruled out any kind of intake gasket leak and only left head gasket leak. This was for when they were looking for the coolant leak (which they found later).

 

You could have a leaking oil cooler inside the driver side radiator tank.

 

I'm going to cross my fingers for this. Thanks Swartlkk. I'm going to talk to the shop tomorrow and see what they say. Is it ok to drive like this? Like i said it doesn't seem to be affecting the drive-ability.

 

Ha, I had to look and make sure that a 92 had oil cooler lines. I didn't see your year the first time I responded. I was kind of on autopilot. But you should have the cooler in the driver side of the radiator.

Now, as far as harm if driven. So long as it isn't a bad leak, nothing catastrophic should happen. If it were to let go, you could push all of your oil into the radiator...

 

Ok, I didn't get a chance to talk to the shop, and I won't be able to for a couple weeks... But, I've been checking the coolant and the oil hasn't increased at all. Hopefully this will stay ok until I can have the shop take a look at it. I just added some coolant today since it was getting a little low. Checked the oil, it still looks fine, not milky.