By March 25, 2008 1 Comments Read More →

Chevy Blazer Heater Not Hot – Thermostat is New

Reader Question

I have a 1996 Chevy Blazer with a 4.3L and the heater blows cold air. I replaced the thermostat and had the heater core was flushed three times( once was professionally done).

I’m not sure what else could be the problem so any information will be helpful. The temperature gauge reads normal temp and the truck is not over heating. This has become very frustrating for me since the weather is still somewhat cold. Thanks for your time and help. Hope to hear from you soon




Howdy Rollie,

I would first feel the two heater hoses under the hood going to your heater core on the passenger side with your bare hands. Once the engine is at normal operating temperature those two heater hoses should be VERY hot to the touch.


1. If the two heater hoses ARE hot, then you probably have a control problem inside the dash not switching from A/C to heat or a problem with the push button control head itself in the dash.

2. If the two heater hoses are cold you probably have a low coolant flow issue….the water pump could have a problem, the radiator could be stopped up with rust, a heater hose could be stopped up with rust or kinked.

3. If one heater hose is hot and the other is cold, you have a restriction in the heater core and it should be replaced……but I don’t think that is the issue.


Austin Davis

Posted in: Chevrolet

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  • Louis

    This really is great! How do you discover these items?