Overheating

[bknox05]

My 2005 pickup with a 5.3 was overheating some not to the point that it was boiling over, but it was running around 235 and the fan would have to run all the time. So I installed a new AC delco thermostat from the local dealership. This cleared the problem up for about two weeks and now it is back doing the same thing again. I assume that I have air in the cooling system and need some input from you guys on the easiest way to get the air out. Or let me know what you think the problem could be.

[FireRed]

When I replace a Tstat I drill the vent hole out to 5/32" it is not enough to make any variance in temp but will cycle air out of the system much quicker.

[daddytech]

first are you losing any coolant through evaporation or just from it getting to the boiling point? second you may want to run the truck from cold with the cap off and top off the coolant until it continues to stay at the top of the neck with no bubbles coming out at all.

If the issue continues after that I would check the hoses for leaks everything from small straigtline leaks to even just a pin hole spotted easily by coolant or just a wet spot mysteriously appearing on a dry hose. also check your clamps , if hoses have been changed and you are still using the factory pinch clamps that could also be part of if not your entire problem. The leak check however would be crucial after everything else has been tried