Slant 6 Overheating

OK--I put in a new radiator cap. Filled it up with plain water and took a drive. The motor warmed up and for the first ten minutes the temp gauge was right where it always is--at the 1/8-1/4 mark. Score! But then, at 15 minutes, the temp climbed up to the 3/8-1/2 point, and I said, "Here we go again!"

So, I headed home, expecting to find my coolant boiled over. But no! I hadn't lost a drop of coolant. Hmmmmm... So, I put in a new 195 thermostat (the old one turned out to be 195 also). Filled it up with plain water again, took it for a ride, and within 10-15 minutes I was up to the 3/8 mark. Arggh--but I figured new thermostat--maybe this is where this one sits. So, I kept driving. It stayed rock steady at the 3/8 mark for 15-20 minutes. I stopped at the grocery store, and when I got back in the car the gauge went up to the 1/4 mark and stayed there. Well, almost. It crept up a bit before I got home.

You know what? I stopped and got two gallons of distilled water, and tomorrow a.m. I gonna drain that radiator, put in a 50/50 mix, and say, "To hell with it!" I think it's O.K. and I think it was a defective radiator cap (thanks for the vote RustyRatRod).

A few days down the road I'll check back in and give an update.