I just acquired a '98 S70, that was supposed to have a blown head gasket. I started it yesterday and it runs fine, however, I did notice that if the oil cap is on, oil flows out of the dipstick, but if I remove the oil cap, it doesn't. There is no discoloration of the oil or coolant, and both are staying at the same levels. So, should I just go ahead and change the engine, or troubleshoot this one some more?