Overheating

[Randy Bellard]

2006 GMC Sierra 5.3 periodically overheating changed water pump twice 5 thermostats drive two 3 weeks no issues then bam over heated again just trying to get a idea of anything it could be before I jump into replacing the Big stuff doesn't seem to be leaking from anything blows heat no leaks inside truck no smell fans do kick on when it is heated just at a loss just don't know if it is the hoses or rad or core 

[Jsdirt]

I'd be looking in between the condenser and radiator for debris. Tree crap loves to pile up in there.  While in there, I'd blow out the radiator with compressed air too.

 

You'll also want to make sure the belt isn't slipping over the pump while your driving, due to a failing tensioner (Which will ruin the belt).

 

If it's overheating just at idle when stopped, you could have a failed low-speed signal to the fan. If you have a belt-driven  fan with a clutch, the clutch could have failed. Belt driven now means the tensioner and belt are even more suspect, since if slipping, there won't be adequate airflow when stopped.

Edited February 27 by Jsdirt

[garagerog]

12 hours ago, Jsdirt said:

I'd be looking in between the condenser and radiator for debris. Tree crap loves to pile up in there.  While in there, I'd blow out the radiator with compressed air too.

 

You'll also want to make sure the belt isn't slipping over the pump while your driving, due to a failing tensioner (Which will ruin the belt).

 

If it's overheating just at idle when stopped, you could have a failed low-speed signal to the fan. If you have a belt-driven  fan with a clutch, the clutch could have failed. Belt driven now means the tensioner and belt are even more suspect, since if slipping, there won't be adequate airflow when stopped.

 

All good points, on the tree crap, I used to live in an area that had cottonwood trees, the worst tree crap of all. I had a '81 C10 at that time amongst other vehicles, I'm not sure if the C10's radiator fins were closer together than in my other vehicles as the C10 seemed to be the only one with the issue, but even after pulling the radiator and back-flushing it with 95 PSI of water pressure the fuzz remained stuck in there so I just gave up and replaced the radiator.