All right I am new to this site but I have looked around and it looks like this would be a good place to get some info on my rides problems. I have a 2001 blazer 4 door 4 wheel drive with the 4.3 vortec v-6 it has about 60k miles on it. All right now that I have the basics out of the way on to the problem my vehicle has decided recently that it does not wish to heat. I have checked to make sure that the air comes out of the right places when you change the them (defrost, vent, floor) and it works fine. I did have the issue that I was a little less then a gallon low on anti freeze added the right amount and that helped for a short while then back to very little heat. I am guessing that i have plugged heater core but a friend says that my thermastat is bad. I was wondering if any one could give a little insight as to the best way to determine which one it is. Thank you in advance for any help that I recieve.

 

Check the radiator level again and make sure it is FULL to the top. Also fill the overflow bottle to the correct level. I have read on the forum that low levels will cause the problem you have.

Make sure to use a compatible coolant. Dex-Cool does not mix with some anti-freeze brands. (Dex-Cool is red in color)

 

If your radiator level got down too far, you may still have air bubbles locked in the system. You can either do a vacuum bleed, or just keep an eye on the coolant level. The bubbles will come out eventually.

And as tomsblazer stated, ONLY use Dex-Cool approved coolant. If you do a complete flush, it is possible to switch back to the green stuff, but ONLY with a COMPLETE and thorough flush!

 

While I'm not related rbarrett, we do have a common last name. Both must be good midwesterners, except for the fact that rbarrett might be a 'Husker.

And I too had heater or have heater problems with my 1999 Blazer. I flushed out my heater core and seems to work better. This week when it warms up to 40'F I hope to flush it with a vinegar mixture. Then I should have a full range of heat.

PS Edited for thread compliance

 

I must have missed something. What does this have to do with a heater problem?

 

Exactly... Finally someone else to be the 'STICK TO THE TOPIC' **** with me. LOL