I have a 2001 Blazer 4.3L(not the Trail Blazer) and the heat isn't working. It will blow out air but it is ice cold and since I live in northern Minnesota this is a problem. The radiator and the heater core were replaced 2 years ago and the t-stat was replaced 1 year ago. One of the hoses coming off of the heater core is hot but the other is fairly cool. The cooler hose is the one that runs to the water pump, so I thought there might have been some blockage with dexcool build up so I pulled the hose off. There was no build up so I put it back on and the heat started to work. It worked great for about a week and now the problem is back. I am going to replace the t-stat again myself and see if that fixes it but I dont think it will, to find the t-stat I just need to follow the main coolant line out of the radiator to where it mets the engine (correct)??? Any other thoughts as to what this might be???

 

Your T-stat is located in the front of the engine on the intake were the big radiator hose goes onto on the top of the engine, remove the hoseon the engine sideandthere will be 2 studs with nuts on them and your T-stat is under there just remove the 2 nuts and give the houseing that the hose was connected to a little tug if needed sometimes those stick a little.

here is a quick how to I just found online http://www.v6z24.com/howto/thermo

As for thecold air I would say have your heater core and radiator flushed at a shop that dexcool is a nightmare I had 68,000miles on my s10 here in WI the frozen tundra in winter just likeMNand my heater was blowing ice cold air, took it in to havethe heater core flushed and they showed me the bucket when they weredone omg what a mess they got out of my heater core, lol almost blew out my water pump gaskets trying to getthe heater core unpluged that dexcool is a nightmare I will neverrun it in anthing I own ever again

good luck its -15 degreeshere right now without the windchillway to cold to be going without a heater[]

 

Changing the t-stat tomorrow with a high of -11 should be fun. I have noticed some build up of dexcool in the radiator so I think I will get the system flushed.

Does any one think there could be a problem with the water pump and itsnot circulating the coolant properly?

Thank you for the help.

 

Like 848 Hooligan said, have a complete cooling system flush (especially the heater core). I would not suspect the water pump at this time.

 

I had the same problem with my 4x41999 gmc jimmy. it would not blow heat. plus it overheated.the dex cool is a good collant but the thing about it is that it starts to brake down and clog up the cooling system. speacially if the truck had sat for along time. the dex cool claims to be good for 150k so the manufacture claims. It doesnt. replace it every 50 to 75k deppending on driving conditions. to fix my over heating probs I replaced my radiator. the old one was clogged. my truck sat for over a year and that caused the coolant to clog up the system.I took the heater hoses and disconnected them from the motor and took compreesed air and stuck the air hose in one of the heater hoses and it blew out a ton of junk. make sure the outlet heater hose is not facing you or anything that you dont want sprayed with junk. It wasnt a pretty site for me!! my heater blows great now. Oh and before I did this I had done two flushes and had no luck. try the compressed air!