No heat/GM

2001 Blazer, 122,000 miles. I have always had coolant/heating problems including replacement of two radiators and I’m on my second heater core (first one blew during a blizzard) and all done by the dealer unil last year. I have learned to live with it but during the winter it is at best blowing 35 degree air. Usually I go into the shop in the late fall(not the dealer) and get it flushed and it held up for a few months. This year, however, they flushed it, suggested I get another core, and it promptly quit the next day rather than slowly fail. There is no way I’m replacing the core again - too expensive and nothing to say it won’t happen again.



They are a good recommended shop and I trust them/



Any suggestions?

This year, however, they flushed it, suggested I get another core, and it promptly quit the next day rather than slowly fail.

Any shop should replace a heater core that failed the next day, unless there was something else going on.

There are a few things that can cause these failures. You need someone who can find and correct the problem, not the result. just off hand I am going to guess an electrical problem. Current where it should not be (maybe a bad ground) can cause this. However that should not cause a failure the following day. That last one may have just been a defective part

Sorry, I wasn’t too clear. When I picked the car up after the shop flushed the core it was heating well (not great) but stopped the next day. They did not replace the core, just flushed it out. No parts were installed, they just did their annual flush and replaced the coolant.