hazmatt9777

Havent found anyone with the same symptoms that Ive got. So here goes. Car : 93 z28 m6 with 81k

Last weekend:
Did a coolant flush, several times
Replaced T-stat with a factory recomended 180 degree t-stat

Got a little warmer, mostly just when the car is idling, but it takes Forever to warm up, im talking 15-20 minutes to get to operating temp while idling (no exaggeration)

This weekend:
Replaced heater core
Did another coolant flush
Bled the system of air (i think)

Car still takes it forever to get to operating temp. When the car idles it will throw luke warm air, but as soon as you take off it blows cold air. If I let it idle for a few minutes the temp will rise to around 200-220 until the rad fans come on and it goes back down to normal temp. The hoses coming in and out of the heater core are warm and the aluminum peices are hot as freakin fire. Id go for a radiator or the water pump but the thing that gets me is that itll throw luke warm air when the car is sitting still at normal operating temp and as soon as I take off it immediately blows cold air again. Do I have a air pocket or a steam pocket somewhere that Im not getting out? When I switch the controls from floor to vents to deforest I can hear the valves shutting and hissing etc and it puts the air where its supposed to with no delay. Ive searched and searched google but havent found anyone with the exact symptoms I have. For what its worth incase they are tied in together in some strange way, the ac system has a freon leak somewhere.

shoebox

If both your heater hoses are hot, then you may have a problem with the mix door in the HVAC housing. It is cable operated by the temp ****. I did not see that you mentioned having checked it.

chevy_dude97

this may sound stupid, does the a/c clutch engage when you turn your heater on?

shoebox

Are you asking the OP or just in general? The compressor does not engage for the heat position.

hazmatt9777

I dont think the compressor is coming on, havent heard it. Alrighty made a little bit of progress yesterday. Checked the cable, its moving properly and moving when I change the direction of airflow. The white **** thats connected to the door seems to be working properly as well. Pulled it up on ramps and bled the system of air again while it was running and got it to blow some relatively warm heat. Drove it around and luckily it was still blowing warm air, but not hot like youd want it. Did another coolant flush, disconnected the hose from the bottem of the water pump and the one on top (where the bleeder screw is) and took a water hose and flushed it out in both directions with good flow. Reassembled, coolant back in, bled system again. It blew slightly warmer air, at idle and continued to work correctly when driving. My question is now, I have a 98 stang gt that will just about burn you the heater is so good, this camaro heat is not hot, or even close to what my ford does. All the old guys ive asked about tell me to run a hotter t-stat like a 195 but they are not aware of the reverse cooling system and that the water is substantially warmer going into the heater core and bottem of the block than the temp guage reads ( it reads 160 at operating temp). Any idears?

moparman

Did you make sure you used the correct t-stat? It's different than the small block Chevy t-stat.

hazmatt9777

Yes. It was identical to the old when I held them up side by side. Let the car idle for 20 minutes this morning and it was relatively warm when I got in. Took off down the road and it gradually got colder, after about 15 miles i turned it off it got so cold. Guy in the shop at work swears its got to be the blend door. Is that door behind the core itself? I dont recall seeing a door when I was under there this past weekend.

shoebox

http://shbox.com/1/hvac_vacuum.jpg

Injuneer

Check 'stat vs. Shoebox's photo:

http://shbox.com/1/tstat.jpg

HVAC control doors, also from Shoebox - the temp blend door is what is operated by the cable:

http://shbox.com/1/hvac_vacuum.jpg

hazmatt9777

Thanks fellas, will tear her down again this weekend when I get a spare minute and check things out.

chevy_dude97

Yeah to the OP, my friends F-bird had the clutch stay on all the time and he only had cold air... it would only blow cold air, After he R2 the clutch it still did the same thing. Turned out to be his vaccum lines going to the controls.
Never hurts to look at everything.