Its been a LONG time since I've dealt with an LT1 but this heating problem throws me for a loop. I get 0 heat at idle, it blows cold air. As soon as I give it gas, instant heat. The higher the rev's the warmer the air.

I've checked the coolant level, air bubbles in the system, and I even flushed the heater core.

Anyone have any ideas???? I'm thinking there's a clog someplace and the high revs cause the water pump to move faster pushing water past the clog thus giving me heat.

 

Do you mean you see air bubbling in the radiator, or do you mean you checked for air bubbles? Are you sure it's bled properly using the bleeder screws? Do you lose any water at all?

 

The bleeder screw sprays solid water when loose, does not seem to be burning anything off either. I'm not sure how I would see bubbles in the radiator but if you mean in the overflow bottle, then nothing. The entire system looks and acts like its functioning properly.

 

You are supposed to use the bleeder screws when filling your radiator, with the car off, after your car has cooled all the way. With the screws open, fill the radiator. When you see coolant come out of each bleeder valve, tighten it. Then top off your radiator. Then start your car, let it run with the heater on full blast, and top off the radiator. Put the cap on once the car starts to warm up. Let the car get to full operating temperature (226*), then shut it off and let it cool down all the way. Then repeat the steps all over again. Sometimes it takes a couple heat cycles to fully bleed the system.

 

I assume you a refering to Heater of your car and not the actual engine temp. The temperature blend door is vacuum operated. Higher rpms under 0% load equals more vacuum. Check your vacuum lines and connections.

 

Thanks...I wouldnt doubt theres a leak someplace. . . .old *** car

 

there is also a coolant restrictor in the system to make sure the heater core doesn't get too much coolant it could very well be almost plugged
it appears to be #13 in this diagram

 

ah... gotta love LT1 cooling system... lol