No Heat!

[WaltL]

Just bought a '95 and drove it home this weekend from DC to GA. What a blast! Anyway, no heat at all. AC works and climate control seems to be ok w.r.t. fan, blower functs., etc...

I've run the climate control diagnostics as per service manual but no codes appear . Troubleshooting section says no hot air is due either to cabin temp. sensor o r the air mix control motor. I haven't started doing diagnostics on those yet. Since I've got no code, am I missing something? Any suggestions?

Thanks

 

[steveny]

I had the same trouble with my car it turned out to be the combination of several things. All the duct work was replaced as well as the air mix control motor. The doors allowing the heat to pass through the duct work were also replaced. I hope you have a strong stomach if you take it to the dealer. I went to see progress on my car and the entire dash was out of the car. I almost fainted:biggrin: . the car looked like someone stripped it. BTW the bill was 4K+. Thanks to an extended warranty I paid ziltch out of pocket. Come to think of it that warranty paid out over 12k+ in repairs, that was a great investment of ~2k on my part. I also think I had a very unique problem as I have not heard of anyone else with the same fix for the problem they have had.

 

[Briank]

First thing I would check if the water valve is connected to the control cable then bleed any air out of the heater core. Is your idle speed normal?

 

[WaltL]

I had the same trouble with my car it turned out to be the combination of several things. All the duct work was replaced as well as the air mix control motor. The doors allowing the heat to pass through the duct work were also replaced. I hope you have a strong stomach if you take it to the dealer. I went to see progress on my car and the entire dash was out of the car. I almost fainted:biggrin: . the car looked like someone stripped it. BTW the bill was 4K+. Thanks to an extended warranty I paid ziltch out of pocket. Come to think of it that warranty paid out over 12k+ in repairs, that was a great investment of ~2k on my part. I also think I had a very unique problem as I have not heard of anyone else with the same fix for the problem they have had.

Ouch! Not what I wanted to hear.
If that's what I'm faced with I guess I better bone up on dismantling the dash... I hate dismantling dashes.

 

[WaltL]

First thing I would check if the water valve is connected to the control cable then bleed any air out of the heater core. Is your idle speed normal?

Brian, that was the first thing I checked. I had my buddy watch as I went from full cold to hot on the temp. control. The cable is definitely hooked up but he never saw it move to actuate the valve. Also, both inlet and outlet lines are are hot so it appears that the heater core is getting water circulated through it which I'd guess is always the case once the engine reaches temp? Anyway, I'm thinking the air duct door isn't opening.

This car came out of VA and has had few miles put on it by the previous owner... he probably never used the heat! If I've got to tear the dash out of this thing I'm gonna be really p*$#ed.

Idle speed seems normal but I haven't checked what normal is (~900?). I'm not sure. I'll check tomorrow and see if it's where it should be.

 

[Briank]

Normal idle is 850 +- 50 just checking to see if the motor is warming up.

The water valve should move, disconnect the cable from the valve an see if it moves. If the mix motor is truly not moving you should get an error when you run the test procedure on the CCU.

 

[WaltL]

When I tested the CCU I didn't run the diagnostics at every temperature, just at each mark on the dial which corresponds to about 2-3 degrees difference between test points. Was this OK?

So if I disconnect the cable, I should be able to manually move the heater core valve... without much risk of damaging anything? Is this valve controlled by the air mix control motor or does that control a damper... or both? If the valve is frozen in position due to lack of use, would that explain lack of any codes for either the motor or temp sensor? I still don't see why both heater hose lines would be warm to the touch. If anything it appears that the valve is stuck open since the outlet hose is warm.

 

[Briank]

With the cable off you the valve should move easily. The test procedure is min temp for a minute and then max temp for a minute. The mix motor moves two dampers that control the mix of cold and warm air but they don't shut completely it also controls the water valve. At warmer outside temps the water valve may not open unless you set max temp. The inlet and outlet hoses could be warm even though you have an air bubble in the heater core.

 

[WaltL]

Re: No Heat...Now No Key Turn

I'll try and bleed any air out tonight... if I can get the car to start (now another issue). By disconnecting the heater valve cable and setting valve to full open, I was able to get some warm air.

This morning outside temp was 35 F. I warmed the car up for about 10 min. at idle then drove the car for about 10 min. cable still disconnected, valve at full open.

After fueling up, I could not get the key to turn in the ignition... not even to accessory position (we've probably cranked the car 30 times prior to this with no resistance and no issues whatsoever). After ~ 2 min. I finally got it to turn and cranked the car. All guage indicators were normal. When I got home, I shut it off and had the same symptoms. No key turn, valet key would also not turn.

Is there any kind of key interlock that physically prevents the key from being turned in the ignition that could be related to my leaving the heater valve @ full open? I kind of doubt it, but the timing of things seems related.

Finally, the previous owner said he never used the heat! Always left the climate control setting at the same temp and only drove on warm days. Not what I wanted to hear since this would indicate that the air mix motor was probably never activated in the last 7 years of driving.

Whay do I feel like I'm getting ready to take it in the shorts?

 

[Briank]

The key will be hard to turn if there is any presure on the steering lock. If thats not the case try pulling the key back a little before trying to turn the keys just be bad copies.

 

[steveny]

Re: No Heat...Now No Key Turn

Finally, the previous owner said he never used the heat! Always left the climate control setting at the same temp and only drove on warm days. Not what I wanted to hear since this would indicate that the air mix motor was probably never activated in the last 7 years of driving.

This is not good. I heard the same thing from the person who I bought my car from.

Good luck!

 

[Doc308]

Re: the key not turning, another thing to do is to spray some graphite lock lube into the igntion switch. I experienced that issue with my '92 and lubing solved the problem for good.

 

[WaltL]

Yea, I used the graphite and key problem solved. :biggrin: Guess the tumblers were a bit sticky, but seems stranage for a 45k mi '95.

Now back to the heat problem:

I checked the cooling level but couldn't really see it too well. Bled the cooling system for air as per manual and didn't see any coming out from any of the four bleeders. Then I added about two quarts of coolant and got the level up.

Now I can detect some heat @ 90 setting (not very much) and it only seems to be decent on upper level fan and only from the vents on the doors... center vent air is noticeably cooler

I talked to a master tech before doing all this and he said the heater hoses should be too hot to touch when the car is at operating temp, mine are not and also my temp guage registers slightly below the midpoint. Could this maybe be a thermostat stuck open? Where is the temp. guage needle normally positioned? I'm going to borrow an infared gun from my buddy and check hose temps. tomorrow.

 

[OLDMNSX]

I had this same problem with my car that I purchased in Dallas, TX. When I got to colder climates there was no heat.

I found that I had a thermostat stuck open.

One of the things that made me suspecious of the thermostat was that when I was driving in a warm climate 60-70 degeres F, the engine temp was slow to rise to a stable level. As the outside air temp (OAT) rose, so did the engine temp needle. It was only a small rise, but noticable. The morning that I left Nebraska the OAT was about 40 degrees and the water temp needle never came up after 30 minutes of driving, hence no heat. I had one of those fold up sunvisors, from the previous owner, for the inside of the windshield and stopped and removed the two radiator brackets and installed the shade, then reinstalled the brackets. The engine warmed up and I no longer was freezing my a-- off. After replacing the thermostat my needle now stays exactly on the mark just below half way. It is solid as a rock reguardless of the OAT once the engine reaches operating temp.

If your coolant level is low, this can also look like a open thermostat. Fill it up and bleed it good. If the bleeders don't let any fluid out, remove them and clean the opening in the bleeder and the housing, a drill bit works great. Just turn it by hand. They can get clogged over time. After you do this start looking for where the coolant went! It doesn't just evaporate. Start with the top of the radiator. Watch for any drops on the garage floor after the car sits for a while.

The original reservoir tank is kind of hard to see the level, so use a Mag-Lite in the opening (engine cold) to check the level. Shine it toward the side that you are looking and it will illuminate the fluid level real well. I took a Sharpie and put a small line at this point to monitor the level. I also did the same thing when it was hot. If I remember right, it is about 1/2 in higher when it is hot.
Brad