Ice Cold Heat

[MUHSFINK]

I've got a 2008 GMC 1500 Sierra and it is blowing no heat, i.e. Ice Cold air. This has happened before, the engine temperature gets up to normal operating temperature and it stills blows cold air. In the past this has fixed itself after I drive for a bit and get the revs up. However it was bitterly cold, -10 this morning and I started the truck to let it warm up before I got in it. 15 min later I left for work and the engine had warmed up fully but it was still blowing freezing air. Convinced that it would remedy itself I revved it up a bit and left. All the way to work, about 20 min, it still only blew cold air even though I had the temp cranked up to 90. The engine temperature was at 210 and never moved. A few months ago I had this same problem but then the engine overheated repeatedly. I managed to limp it into the dealership before it lost all of its coolant. The tech said that a coolant pump had exploded and everything was fixed. Are these two incidents related? I assume that they replaced the coolant properly, no air pockets or anything but I may be mistaken. Any help would be great. I really don't want to become a human popsicle INSIDE my truck.

 

 

Cheers.

[txab]

Check for trapped air pockets and bleed if necessary. Might want to make sure your heater core isn't stopped up. You could have a blend door problem

[8.1HD/ALLISON]

Shouldn't have any air pockets anymore after driving very far at all. I would be willing to bet you have an issure with temperature blend door motor.

[MUHSFINK]

Shouldn't have any air pockets anymore after driving very far at all. I would be willing to bet you have an issure with temperature blend door motor.

 

 

Thanks very much! I'll have the techs take a look at that when I take it in for its next service.