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68gmsee · 05-03-2010, 10:43 AM

Before replacing the pump, I'd take it in to a shop to do a leak down test on the radiator to see if you have a head gasket leak somewhere.

I had a similar issue on a Chevelle I used to have. Gradual increase in temp and eventually spilling out the cap. IIRC, mine turned out to be a hairline crack on one of the heads.

On some but not all radiators you can look in the cap opening when engine is cold and see the bubbles.

05-03-2010, 10:43 AM	#4
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: random overheating Before replacing the pump, I'd take it in to a shop to do a leak down test on the radiator to see if you have a head gasket leak somewhere. I had a similar issue on a Chevelle I used to have. Gradual increase in temp and eventually spilling out the cap. IIRC, mine turned out to be a hairline crack on one of the heads. On some but not all radiators you can look in the cap opening when engine is cold and see the bubbles.