2000 3. slow 158,000 miles
I recently was driving home late during a snowstorm on the back roads when I noticed the temperature gauge rising and falling. I periodically stopped to let the engine cool, even though I couldn’t see where the shoulder of the road was.

The last time I let it cool, the needle on the temperature gauge got above 3/4 of the way—I had to make it down the hill first and cross the bridge to get out of the way before stopping. Hopefully the engine didn’t overheat and warp the heads—It did not go into the red. Remembering I had some coolant in the bed, I topped off the radiator and drove home.

Today I rented a block tester and discovered that cylinder 4 turned the fluid yellow while cylinder 5 mostly foamed. I am thinking the head gasket is bad. Engine oil is not contaminated and haven’t seen white smoke from the exhaust. A head gasket would explain why I’ve had a coolant leak that I haven’t been able to externally identify with a cooling system tester.

Looking for advice on how to proceed from here, should I order a head gasket set with new bolts or tear into it first and evaluate? Is there anything else you suggest to replace along the way? I’m considering rebuilt heads but it’s such an old dog.

Pull the plugs, if they are super white good chance that cyl is burning coolant, then you can proceed from there.