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I took my wife’s’ truck into the dealer yesterday. With the coolant blowing out and the system staying pressurized, I was expecting a blown head gasket. I explained everything to the service writer. I got a call yesterday after noon from the dealer saying it was fixed.

When I went to pick it up, I was told that the thermostats (2) had been replaced and that an exhaust gas test was preformed on the coolant and came back negative. I was also told that the Duramax will build up and hold pressure in the radiator even when cold. That seemed a little strange but that is what I was told.

While the truck was in, I ask them to look at two intermittent switches, the mirror control and the dome light switch. Also the temperature gage seemed to be sticking. They replaced both switches and fixed the temperature gage. I think this dealer is on top of things. I have gotten good service and very little argument. The Dealer is Jerry Barker Chevrolet in Byron Georgia.

While I am on this subject, has anyone else experienced pressure in the colling system when the engine is cold, not cool but over night cold?

Keep an eye on it.

I don't mean to sound negative but I replaced my thermostats and all was well for a week. Then it started again.

As far as the exhaust gas test is concerned... that is the good news. Maybe all is well.

Mike

I'll take the optimistic path ...


Glad to hear it, the negative test on combustion gases in the coolant was welcome news I'm sure ...


Good luck, glad to hear all is well as it appears...


Mac

There should not be any pressure difference when the engine is cold and you need to add coolant. That was a key symtom in my failure as there always was some pressure difference whether the engine was cold or hot. I had a difficult time adding coolant even when the engine was cold. When I opened the cap, coolant would come out the overflow tube (engine cold).

After the repair, which went very well I might add, there no longer was a pressure difference when the engine was cold.

Edited by: hoot