Greetings 450,

Is the oil that appears in the overflow tank consistant? What I mean by thatis, does it reappear after either flushing the tank or blotting it all out? I'd fully flush the tank and try this one over again. The next thing is that seeing as you have good coolant pressure, maybe to much from what you say, could be a stuck thermostat at those constant temp readings. If it were me I'd check the following items. First blot the paper towel into the oil in the coolant tank, and let it sit till the coolant has dried and only the oil remains. Does it smell like tranny fluid then? If it does, then you probably have a radiator leakage from the tranny fluid line internally, which is a better case senerial. If you are convinced that the oil on the paper towel is engine oil then drain the engine oil into a clean pan and visually inspect it for the coolant which should be quite evident. Pulling the dipstick won't tell you the story unless you have a massive leak of antifreeze into the engine. Coolant pressure is higher than oil pressure thus you should have coolant flowing into the lubrication system until the coolant cools down where by leaks only through cracks in the block would allow oil into the cooling system. A leaking tranny line that goes through the radiator would be my first guess culprit if I were guessing blindly.

Charles