Where can I get a low temp thermostat

[shan1111]

Hi all, I have a 08 Yukon with the 5.3l and the fan seems to running almost all the time. I was going to do a rad flush and figured I would change the thermostat at the same time. Also figured I would go to a 180 degree one if I could, but I can seem to find anybody that sells them. Anybody have any ideas?

[Wolfmanjohn]

JMO, but stay with the stock temp. These motors need to run at a certain temperature in order for the PCM to operate things correctly. Now, if you have a custom tune, that's a different story.

[Carder09]

I don't see why your worried about the fans operating. Their job is to keep the engine cool and being that they are electronic and not motor driven, your not loosing any power from the motor when they are running.

[AirForceAngler]

If I'm not mistaken, if you put in a cooler thermostat without adjusting the tune, the engine will probably run rich (warm-up mode) the whole time as the computer is sensing that the engine is not ever up to operating temps (~210). This will kill your mileage. If everything is running as it should be, don't mess with it.

[dewfpo]

If the fan is running almost all the time, do you leave the HVAC in the defrost position? Do you leave the A/C ON in the auto temp setting? Either of these will make the compressor come on and the fans will run.

 

DEWFPO

[MikeNH]

Don't swap the t-stat.

[Wires]

Hypertech makes a 180F one that won't cause issues with the stock tune. Ran it in my 5.3L for a while, then ended up taking it out. 195F is the best balance for power/efficiency. You'll start losing MPG with a lower t-stat.

 

If the fan is running constantly, I'd be looking for root cause of that first.

[shan1111]

I am running with a K&N CAI, a magnaflow cat back exhaust and a SuperChips performance tune.

 

The heat issue started about a month after I did the tune, so I am not sure if it is related. I know it is running hot, there was one day where it is -35 outside and the temp jumped up to about 220-225 when idling for about 10 minutes (this was after I was driving around a bit so the truck was at temp when it was left).

 

Anybody have any ideas what the cause of the heat might be?

[00Silverado4x4]

I am running with a K&N CAI, a magnaflow cat back exhaust and a SuperChips performance tune.

 

The heat issue started about a month after I did the tune, so I am not sure if it is related. I know it is running hot, there was one day where it is -35 outside and the temp jumped up to about 220-225 when idling for about 10 minutes (this was after I was driving around a bit so the truck was at temp when it was left).

 

Anybody have any ideas what the cause of the heat might be?

 

Thermostat stuck closed

Water pump not turning (probably not without some other indicators)

Radiator blocked up (internally)

Low coolant level (or even NO coolant level)

One of the fans not turning

Air flow blockage across radiator

Radiator hose blockage

Radiator fins blocked with road debris preventing air flow

Air in the coolant system

 

Just a few ideas off top of my head.