Is it possible...

Dirtygirl22 · March 30, 2022

Is it possible for your truck to 'burp' itself? Let me explain, my truck, an 06 GMC Sierra with 5.3, had a leak in the radiator and was overheating,so I changed it. OK it's still overheating, so then I changed out the water pump,still overheating. Changed the thermostat and I cleaned out the heater core, still overheating! so I did a compression test on it and it failed. you know the blue turned green. Head gasket. so I parked it until I can afford to fix it. so I parked it until I could afford to fix it. it was about 2 months I guess, that she sat. maybe that's that And I hopped in it today, she fired right up. I was taking her to the garage, expecting it to over heat before i hit the end of my street and ive been driving her for 2 days and no overheating. Hmmmm? Please explain.

sharkeysierra · March 30, 2022

Maybe it just needed a break?

Give it a week, problems may creep back up or maybe weather in Mesa has been cooler this week than normal. Sometimes the issues fix themselves and we never know what the fix was. Pretty much like hitting the steering wheel or dash in certain situations.

Apologies for the randomness of the post, haha

Palmhat · May 13, 2022

Well, I guess I'm a bit ahead of you. Replaced the heat sensor which activates the fans. I replaced the thermostat twice, replaced the water pump, replaced the valves & surfaced the heads because the #4 cylinder was down to 85psi dry test. no water in the oil & was told it was likely venting into the water jacket. Valves were iffy & truck has 200k+. Thinking the head gasket was the issue & everything was opened up, might as well while we're here & I don't want to come back for a while. none of these solved my problem. Still overheated with in one tenth of a mile. Had the radiator tested & was told it was 85% good. So what else are you gonna do? Dropped in a new Radiator. Still overheating. I'm in over $2300. My buddy comes down from his off-grid mountain homestead & pulls the coolant reservoir cap and shows me that the lower "O ring" is chipped. explains that it is compromising the atmosphere so that the boiling point is lower & therefore pushing coolant out the overflow while driving. This explains why we never saw any coolant leaks while parked. At O'Reilly's it cost $11.

That was in January & here we are in May & the truck is overheating again with the reservoir low. Will l be paying too much by ordering it from factory?........

I actually was hoping to find out what the operating temps are for the cooling fans but thanks to your question I will opt for the new cap. After all, it did work for a while.....

But your question was about self burping. I would not count on it but welcome to Chevy Mystery Theater. Mine sat for months before it got running again, but then it was running & the coolant is going somewhere... Please let us know if you find resolution.

Edited May 13, 2022 by Palmhat