Black goo in radiator

[bfarroo]

I noticed that the temperature gauge on my spirit was running a little higher than normal today so I checked the radiator after it cooled and there is some black goo on the bottom of the cap. I'm assuming oil is getting in. The oil level is normal, maybe a little low(1/4 qt) but there are 3000 miles on the oil. The plugs all look good also. My thought is the head lifted under boost and let some oil into the cooling system. I pulled the valve cover a re-torqued the head bolts and they seemed to get tighter than they were but the bolts could just be stretching more. What do you all think? I'll probably drain and flush the coolant this weekend and replace and monitor it. Hopefully it will hold up unit I have time to pull the head and look things over. I can always drive the truck if I have to so the car can sit. I just need to put my time towards getting my 89 csx finished before SDAC. The car does have a chinese replacement head on it that was on it when I bought the car. Doesn't smoke and don't see any bubbles in the radiator when running. Engine was refreshed about 50,000 miles ago with new bearings, gaskets, and rings but wasn't bored, just ball honed and cleaned up. Let me know what you think.

[tman1999]

have you mixed antifreeze like have to add the all makes all models stuff to it? ive seen it before people mixing them and then sludge comes.

[bfarroo]

I flushed and changed it last year. Don't remember what I put in. I think it was the all makes stuff. I'll probably change it and put the green stuff in.

[4 l-bodies]

Black goo is probably rubber hoses starting to get soft and decompose from the motor oil. 10+ years ago I had a tranny cooler (inside radiator) that sprung a ATF leak. It was on a very unusual vehicle. I ended up having to replace every rubber line (almost all of them molded) in the cooling system which because of the type of vehicle was around $700. This was in addition to flushing it out about 15 times to get the ATF oil out. Of course had to replace radiator too which was another $450 or so. It was a costly fix for an odd problem to have.
Todd