No Heat (Tryed Almost Everything)
 

I have searched the forums for this thread and i can't really find much that will help me so im just going to ask.

Bascially I have no heat it gets slightly warm, but hardly warm enough to defog the windows. We've changed the thermostat. I've just drained the car from the bottom of the radiator. Also the lower radiator hose on the left side if you are facing the front of the car. I have also flushed the heater core both ways and it is clear both ways. I thought it could be the heater control valve, but there was lots of antifreeze in the heater core when i flushed it. I have purchased the heater control valve and heater core, but i am trying to diagnose this because i assumed when i flushed the core there would be lots of gunk and restricted flow, but its fine or seems that way. I have also removed the coolant resevoir and cleaned it out. The radiator has also been pressure tested and is fine. Any advice or suggestions on what i should do next would be greatly appreciated.

Also i can't seem to figure how to remove the stock heater control valve.
And I also am wondering how the heater control valve works? is it like a thermostat?

Oh yeah i have a 1997 Z28 LT1 No modifications except K/N air filter.

What kind of coolant temps are you seeing on the dash gauge? Have you verified that the coolant is getting hot, and that it is heating up the heater supply and return hoses? The LT1 flows coolant to the heater core all the time. There is no flow control valve. There is a small flow restrictor in the supply hose.

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

Have you verified the flapper doors in the ductwork under the dash are working properly when you move the controls? They are vacuum operated, and if you have a leak in the vacuum system for the controls, they will not work.

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

Did you burp the air out of your system?

Yes i used both bleeders valves to get the air out. Will their typically be alot of depris or congestion in the heater core if it is the culprit?

Also how can i check to verify the doors are working correctly..The A/C works fine, idk if that matters and i see the diagram, but where are the actual vacums located.

I've checked the vacums and when i switch from hot to cold you can physically hear it switching the door. I have bought a heater core, but do you think it is necessary to install a new one since i didn't get any gunk and it flowed properly?...or should i just refill/bleed?

Check the coolant level in the RADIATOR, not the overflow.

I have heat...but its saying low coolant

when i went to refill it i followed shoebox's procedure.
I filled the radiator
filed the reservoir to full cold, both with the bleeders open
waited for actual coolant to come out of the top of the radiator and then put the cap on. Then as coolant was coming out of the bleeders i closed them.

I let the car warm up and its still saying low coolant. The resevoir is still in the same place as before. I thought the radiator pulled coolant from it as needed?

What should i do guys?

Did you check the level in the radiator? Don't check the reservoir.

The low coolant sensor failure is a common problem on these cars. If you can verify that the radiator is full, by (carefully) removing the radiator cap, then the sensor is bad. You can unplug it and the light will go out, or you can replace the sensor (a few inches below the cap). It might be possible to clean the sensor, and its worth a try.

It is also possible that if there is a crack in the hose from the radiator overflow to the reservoir, the vacuum in the radiator can not pull the coolant back in from the reservoir.

But as has been suggested, verify that the radiator (not the reservoir) is full.

I though I would get air in the system if I opened the radiator cap after I've bled it. dosent the resevoir provide coolant to the radiator when it needs it.

No, you won't get air in the system by removing the radiator cap. Check the radiator. You might just be low on coolant.

"What we have here is a failure to communicate."

:D

Ok i've been refilling this damn thing all night. So I filled it up and kept adding til it was at the radiator neck, put the cap back on and then let the car cool. Its still at the top of the radiator and its slightly past the FULL COLD on the reservoir. I then drove the car to the gas station and it still shows low coolant.

Are you actually reading the information people are trying to provide you with?




"What we have here is a failure to communicate."