Can anyone help me with this one? I opened the radiator this weekend and saw a strange white to gray slime on the top of my coolant. I almost looks like mold or something like that. I have a new radiator hoses ect. All have been in service about 2 yrs.

What kind of coolant? Orange Dexcool, or Standard green antifreeze. I've seen it on the bottom of the radiator cap and around the fil neck of the radiator in Dexcool cars. Looks sort of like a very soft white to grey colored grease. Never seen that in a green antifreeze equipped car. If it's Dexcool you're in the early stages of an air leak into your radiator and the coolant is starting to breakdown, on it's way to mud. Flush it out and refill. Find out where the leak is. Possibilities are a leaking radiator cap, or an empty overflow jar sucking air back into the radiator when it cools down. Dexcool should never be used in a car without a recovery tank.

It’s just the green stuff. I do have a recovery tank but it is empty. I don't think these cars had one originally, but I put one on when I was trouble shooting some overheating issues. I found out my problem was a defective cap.

The only time I’ve had that was when I blew a head gasket, I had water in the oil and oil in the water…

Oil definately will do it. Another source of the sludge is from a leaky automatic transmission cooler. The condition has been called strawberry milk shake. Of course the strawberry part comes from the tranny fluid being red. Sounds like the other two guys probably have identified your problem - coolant breakdown or engine oil. Check your oil levels and see if you have a similar slime there.

No signs of water in oil or trans may be just coolant break down. I'll change it and see what happens.