My little s-10 blazer doesn't push heat like it should. I just repleced the thermostat, and the blower fan works fine, the air just won't get past slightly warm. With witer coming and this being the family truck, it is a pretty big concern. Anyone have any suggestions?

 

First3 things I would check would be to see if the baffle inside the ducting is moving all the way over to block the cold air side, it's probably vacuum operated so there's a chance the line has come off or is leaking...or #2 thing would be something has dropped into the ducting and has landed right where the baffle is and it's stopping it from sealing off the cold air side. Do you hear any sound when you select from cold air to warm? you should be able to hear something, air movement or the baffle moving. #3 would be your heater core is plugged...I would try dis-connecting the 2 water lines and running a garden hose into the heater core to check the flow, when I flushed out mine a while back there was next to no back pressure. Good luck...no heat sucks in the winter.

 

sunshine coaster pretty much hit the nail on the head. in my experience #3 seems to be the most common cause. good luck fixing it iknow exactly how you feel. i spent all last winter in a '91 S10 with NO heat at all.