So, I'm one of the many people having heater problems right now. For awhile now, I've had NO warm air output from my heater vents. When I run the warm/cold slide control back and forth with the blower running, you can feel a change in the velocity of the air, and also hear the door behind the dash opening and closing.
Today, I removed my heater control valve and installed a flush tee. I ran water through my heater core (inlet line hooked up, outlet disconnected, and a vise grip on the line BEHIND the tee going back toward the engine. Water ran through the core no problem, and seemed pretty clean from the gitgo. I then hooked up the lower heater core line, removed the vise grip, and started the car with the water running and the rad cap off. It started pushing water out of the top of the radiator, and I let it go for a few minutes until the water was clean.

I also replaced my water temp sensor this morning, as for several months, my temp gauge would lay on the peg for awhile, then JUMP up toward hot, and then settle down in the normal range. This was only an intermittent occurence, so I just kept an eye on it for awhile.

QUESTION: Could the intermittent water temp sensor misinform the heater control valve, and not let it open (allowing coolant through the core and heat into the car)????

I've priced and located the heater control valve and a new harness (apparently valve was somewhat redesigned since original manufacture), but don't want to drop the $$$ if the temp sensor might have been the problem... The control valve is clean inside, but it is vacuum-operated and also has electrical connections, so I'm not sure how to t-shoot the valve itself.

Many thanks to anyone who has some ideas...

 

shiet!
i'm in the same boat
are you certain your air/mix door is functioning properly.

 

Where is the air/mix door Ryan? I'm still having issues like you guys and something tells me a coolant flush won't be the answer, as I can still get full heat, but only when I floor it. Then it dies back down to about 30% efficiency after about 30 seconds.

 

or are you just refering to the actual door lever on the heater controls. You probably are.

 

UPDATE- I refilled my radiator yesterday (as I mentioned above), and my heat seems to be working again. I filled it from the firewall with the Prestone flush tee while my heater control valve was removed. Maybe I purged some air while filling this way- I don't know. But for the first time in a year or so, it seems to be working...

 

Well that's encouraging. So you did it from the firewall and then put the valve on after. Hmm... worth a shot. glad you got it working! How long did it take you to do all this?

 

does ur A/C always work or is it just mine thats ****ed up? cause even if i set the climate control to the warmest temperature, the a/c still seems to be working, since the hose that goes from it is always flozen over on top... that seems kinda weird to me...

 

xplOsive what are you doing here mang? Did you get that turkey sub yet? lol.
Hey at least your A/C works. Alot of 3rd gens complain in the summer that the A/C sucks. I am one of them. To answer your comment: my A/C isn't interfering with the heat, the heat is definitely there, but isn't making it's way to the cabin.Your thing is wierd. Shock211 will probably have an answer for ya. Maybe your a/c button is stuck in the on position?

 

if the front windshield defroster is on your A/C is running.

 

the problem is that there is no a/c button... i have an automatic climate control thing... anyways, when i try to heat up my car, i always turn on the windshield difroster, and it kind of blows somewhat warm air out of it... but the front 4 blowers are blowing ice cold air... mite be that my climate control unit is ****ed.... ill take it apart over the weekend and see whats wrong....

 

and no im still working on that turkey sub... found a good MTX 8000 deal... mite go for that

 

almost sounds as if you have a/c AND heat engaged

 

yeah thats what im thinking too, so how do i turn it off... i was just thinking of pulling the wire out of the a/c....

 

Honestly, I don't know how to turn it off manually other than to pull the fuse, which would be much more efficient than pulling the unit itself. I'm sure one of the other guys will have suggestions beyond that.

 

Most automatic climate control systems in most cars appear to run the a/c when the heater is engagued. It might also be a factor of the computer knowing what the outside temp is and the inside temp and figuring that if the outside temp is cold, you will want to keep the a/c running when heating the car to suck the moisture out hence preventing and/or removing frost/fog on the windshield.

I know that on my 2 other cars with automatic climiate control, teh a/c unit runs a lot when its cold out.