I was thinking the same thing about the spot inside the oil cap. Been frosting and thawing here regularly. Don't have the gear to pressure check and honestly don't know how to anyway. I haven't checked to see how the radiator flows, I'll give it a try later today. As far as the oil leak goes I figure that the leak is somewhere along the timing chain cover. But I'm not sure where and even if I did I'm not sure if I want to pull it off to fix it...yet. Guilty on not having changed the t-sat for a while!!! I was thinking that I'm gonna head out and buy me one of those dual valve t-sats that a few folks on here rave about. Seemed to me that the minimal spike in temp was the t-sat not engaging when it should have. Good thing is that the temp only rose ever so slightly and lasted only a couple of seconds. Might just be a conicidence that the temp glitch and this spot inside the oil cap happened to be found at the same time! After looking around I'm gonna forget that I even suggested re-torquing the head bolts....desperation may be setting in!!!