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.