GoldOlds

Upon returning home from the in-laws, I noticed the rapid spillage of coolant onto my driveway. I popped the hood and discovered the overflow tank (a homemade jobie done by the previous owner), well, overflowing. The temp gauge was between 180º and 190º through the entire 35-mile journey (mostly highways) - the outdoor temp was about 60º. I suspect the rad cap is the culprit, but I'm not sure if it could be the thermostat or not; a cheap, easy fix either way, I suppose.
Any guesses?

- GoldOlds

Dapapadon

I'd start with the cap. Cause they're cheap & only take about a minute to change, with the engine cold.

Don

Oldsguy

I agree, do the cap first. It is probably not holding pressure, so you get the overflow.