Ok, stupid question. I got in my truck this morning and drove my truck for 45 min to work. normally my heat is ready to run me out of the truck at this point. But today it was still blowing cool air. I am thinking it must be the thermostat. So i looked it up and my 03 D-MAX has 2 thermostats. Do I need to change both? or just one? Also how hard of a job is it on my truck? Any help would be great. thanks. I am going to need heat soon, it is getting cold outside.

 

Think the other thermostat is for the transmission.

 

really? that makes sense since it has a trans cooler. Anybody else?

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BUMP BUMP.......any idea which thermostat i need to order?

 

Run down to a GM dealership (parts dep.) and let em know you need one for the coolant system. They'll hook you up.

 

One other thing you could do is take the heater hoses off and flush it out with a garden hose. A plugged heater core can't let hot water through to heat the inside.

 

Updates??

 

well, the truck actually hasnt had a problem since my first post. So I have delayed the repair. I talked to the gm parts guy, and he said both thermostats are used for engine cooling, but could not tell me why it was designed that way. LOL i will prob end up changing them one cold morning with my luck haha

 

I changed both of them a couple of months ago. It is not that hard on the LLY. Total bolt count was less than 20. The hardest part for me was to get the housing up without breaking loose the hard line coming into the t-stat housing. Look up how to change a thermostat on the forums. Do not overtighten the t-stat housing bolts. If you break one, you will be way up the creek without a boat or paddle as the soft bolts go into a softer aluminum base.

 

thanks for the usefull info. I dont think mine has quite 20 bolts.

 

Updates??