Why does my heater blow cold air even if I set the temp to 90?

[Ozz]

Burping it couldn't be easier... Take the plug out of the crossover tube in front of the alternator with a 1/4" square driver, fill the tube with coolant, put the plug in the hole loosely, start the car and watch for bubbles come out, tighten the plug when only liquid comes out (as the car warms and the fluid expands).
Probably a good idea to do this a couple of times.

It solved my problem.

 

[Illss]

Sorry to bring an old thread back to life but i have the same problem an noticed that my temp changes even with the a/c on !! :help:

 

[RCSignals]

Sorry to bring an old thread back to life but i have the same problem an noticed that my temp changes even with the a/c on !! :help:

If the change is big it could be the problem described here.
If small changes it could be the HVAC system automatically adjusting to keep the temp you selected

 

[03blackmerc]

Air Bubble

i recently had the same problem, i replace the thermostat and still no heat. i talked to the guys on here about it and they told me to start the car let in warm and make sure the front end is up. let it go through one or two hot cold cycles once completly cold(with front end up). open the plug at the highest point on the coolant system you should here air seaping out. Anti-freeze should also be right to the top showing no air in the system.

 

[RF Overlord]

Ancient Thread Alert.

 

[sleeper]

I am having the same trouble with no heat. I "burped" the system today twice and no good. I read on this thread that the front end should be up and then "burp" the system. What does having the front end up do? Thanks

 

[RF Overlord]

What does having the front end up do? Thanks

You don't actually NEED the front end up, just be sure the car isn't facing downhill at all. It needs to be at least level to burp properly.

Unlike your father's Oldsmo-pile, the reservoir is not an "overflow"...it's part of the pressurized circuit and is not the highest point in the system; the bung in the crossover is. If the car isn't level (or facing slightly uphill), you can get air trapped in the back of the motor. It will not naturally bleed out through the reservoir.