I've got a 2000 S10 Blazer. Been having heat issues for the past couple of winters. Last week I put in a new thermostat since it wasn't getting up to operating temp. Thought maybe I'd have heat. Didn't work. Next I changed the dash control and then the Blend door actuator. Still no heat. It's blowing cold and the air is coming from every vent. Doesn't seem to matter where the selector switch is. Any help would be much appreciated.

 

Sounds like your Heater Core is plugged up. You still using Dex-Cool for cooloant?

 

Hi the follwing suggestions may help for you ....

Check the vacuum lines running from the intake manifold over to a tee near the brake vacuum booster and on to the vacuum resevoir in the left front fender. Very common for these to rot and leak with age, and will cause the symptoms you have described (or)The first thing you should do is go to the dealer and get them to copy the diagrams from the parts catelog. There are acouple of them that show different views. Also get the pages which list the parts and description that go with the diagrams.
this will help you find the baffels or doors that control airflow and the parts that control them. Check the hoses at the firewall going in and out of the heater to see if they are hot.

 

i dont know whats going on but ive been working as a mechanic for about 6 years, the last 2 winters we have been getting slammed with clogged heatercores, i even have to flush my gf's liberty tomorrow cause its the same way.

everytime i flush them into the bucket its always the same crap in there, its like orange and brown basically looks like someone put a old cork gasket into a blender and put it in the radiator. its really simple to do and only takes about 10 minutes. hardest part is usually getting the rotted hoses off.

come to think of it i just did a s10 the other day you dont even have to take the hoses off the heatercore, theres one on the intake and one that goes to the water pump so you have lots of extra hose to work with. i just flush it both ways with the garden hose about half blast each way twice

 

Did you get your problem resolved?

 

im interested in this as well, mine is blowing cold too.

Im thinking my problem is the old dexcool that will be getting changed next saturday.