Heater Trouble PLEASE HELP !!!

[Pedantic.2012]

Hello, I have a 1998 Buick LeSabre Limited. I recently replaced the water pump, flushed the radiator, replaced the thermostat, and bled the radiator for air lock. Now, when I turn on the heater I get mediocre heat only on the drivers side and freezing cold air through the passenger side. It also over heated the other night but has not since. This car used to have phenominal heat. My mechanics are totally baffeled! Thank you in advance, Susan

[imidazol97]

Originally Posted by Pedantic.2012

Hello, I have a 1998 Buick LeSabre Limited. I recently replaced the water pump, flushed the radiator, replaced the thermostat, and bled the radiator for air lock. Now, when I turn on the heater I get mediocre heat only on the drivers side and freezing cold air through the passenger side. It also over heated the other night but has not since. This car used to have phenominal heat. My mechanics are totally baffeled! Thank you in advance, Susan

Why did the car overheat? Was the radiator coolant low inside the radiator even though the reservoir tank may have been full enough?

If it overheated due to low coolant, why? The most common problem is leaks in the upper intake manifold and the gaskets on the lower intake manifold between that metal part and the heads.

Did the person flushing say that the old coolant was badly cruded up? The scum from not changing it or mixing green old style with the DexCool in it may have partly clogged the heater core.

Did the person flushing make sure the heater core had the air out of after refilling. You might try doing that yourself: after the engine is nice and warmed up such as a 15 minute drive, run the motor at about 2500 rpm for 10 seconds, idle, then repeat 4 more times. This is supposed to push air out of the heater core. If you can park the car with the front end uphill while doing this, it's my personal thinking it helps get the air out of the heater by having it as low compared to the radiator and engine as possible.

Because you say there's a radical difference between the passenger and driver side, this might be a problem with the electric actuators that move those two doors on the heater box. The actuator for the driver is on top of the heater box. Sometimes those develope a slip inside the electric part with plastic gears due to a cracked gear, and they don't move the door all the way. Do you get a flashing of the digits on the dash temp control after starting the car for 90 seconds?

The passenger side actuator is at the bottom and uses a rod from the programmer to the door. That might have unsnapped from the plastic arm coming out of the heater box. These are accessed by removing the plastic hush panel under the dash with 3 screws and 2 taps against the firewall.

[Tech II]

If this all happened after replacing a w/p, chances are it's an air pocket.....

[Pedantic.2012]

Thank you so much for your help ... @ imidazol97 ... #1. Don't know why it over heated, have checked fluid levels and they are up in both the radiator as well as the resevoir. Last night I closely watched the temp guage on my way home from work and even though it did climb a bit I actually saw when the thermostat clicked in and the temp dropped. #2. Don't know that it was cruded up but it was mixed and so we replaced it with the correct antifreeze. They did "Bleed" the system of air with the 2500 rev proceedure. #3. I do indeed get the flashing digets on the dash temp and it happens just as you stated. Afterwards it stops. I thought it was coding and told my mechanic about it last night. I thought it was due to replacing the battery. I'm going to print your reply off and take it over to my mechanics. Thank You so very much for your imput. I'll let you know how we make out with this. Many Thanks Again!!!
@ Tech II ... Thank you also!!! I will ask them again to bleed it out for and air leak but now on an upgrade.

[Pedantic.2012]

OK ... took my car in and here's where we're at: Bled the system of all air, followed your directions, ie; 2500 rpm for 10 sec. and repeated 5-8 times to be on the safe side. Also bled the thermostat housing. All was good. Felt the heater hoses going through the engine compartment firewall to the heater core and they bother were warm.

On the way home immediately after starting the car I did hear a weird noise coming from the glovebox area. Like something trying to move and then it stopped. The ice cold air from the passenger side did actually go luke warm-ish after that. Also, the digital temp continued to blink. I counted the flashes and the first time it blinked 33. After we had shut off the car and restarted it again I counted and this time it flashed 16 times. I could be mistaken on if I counted the flash once too many times so either of those could be 32 & 15. I looked up the code the best I could and all I could find was a diagnostic trouble code key for a 1993 GMC and those codes meant the following: 33 = MAP ... Manifold Absolute Pressure Sensor Voltage High. 16 = Vehicle Speed Sensor Buffer Fault. Which really didn't make much sense to me, however, code 15 was Coolant Sensor Circuit Open which was in the right ball field at least.

We also inspected the engine for any sign of leaks and found none. Next step I guess would be to tear into those actuators.

Please feel free to toss in anything else you might think could be the problem here ... what else we might check.

Many Thanks Again!
Susan

[HotZ28]

You probably have a broken gear in actuator for the blend door.

[imidazol97]

Originally Posted by Pedantic.2012

I looked up the code the best I could and all I could find was a diagnostic trouble code key for a 1993 GMC

The HVAC control unit was set up to use a flashing code to try todiagnose some problems only through 93 or through 1994. After that, it requires a TECH II or other higher level interface unit--the typical code readers the Autozone here loans or people buy only read the usual codes for the car but not the HVAC units.

The one comment I have about the heater hoses is that after the engine has warmed to temperature, they should be very hot. The ingoing hose will be warmer than the hose with water leaving the heater core. The blower should be on High and the engine car be revved above idle for testing. The out going should not be cooled down substantially cooler with the higher flow at 2000 despite the blower air taking lots of warmth from the water in the core. If there's something reducing the flow in the core, that lets the air take more warmth from the metal and the water, so the out-coming water is cooled a lot. If you have another vehicle, try feeling both hoses on it under those conditions to compare the temperatures.

The link for the lower actuator might be off, and that is easily checked visually after the underdash panel is off. I'm curious that you're not getting heat from one side or the other: both actuators would not be broken. That's why I suggest checking the heater core temperature when the engine is up to full temperature. When the upper actuator was slipping on mine, the passenger side would get moved to nice and warm while cool air was coming through the blend door with the upper actuator slipping and not moving the door. http://i86.photobucket.com/albums/k1.../heaterbox.gif

[Pedantic.2012]

Latest update: We just removed the glovebox and found the acuators. There was one on the top of the heater box and another arm moving below the heater box. Both were in sync and moved back and forth smoothly when we started up the car. Does this mean that it's not the actuators then?

We do have another vehicle and will next compare the heater hose temperatures between the two.

As for the heat temp on either side: Drivers side has good heat, it doesn't seem to be as good as it was before this problem came about but nonetheless it's definitely hot. The passengers side was ice cold, as if someone had turned on the A/C at it's lowest setting. But yesterday, after we heard that noise coming from the glovebox area, the passenger side did actually get a little warm. Luke warm and cold air both being blown through the vent together. Meaning there were cold spots in the flow. We haven't actually let the car warm up to temperature today to check if that warming is still there or not. We will be heading out in a few and will perform all other suggestions when we return as the engine will be at full temperature at that time. I'll post again with the results when we return.

THANK YOU AGAIN FOR ALL YOUR HELP IT IS SOOOOO GREATLY APPRECIATED !!!!!!!!!!

[imidazol97]

You can push on the arm of the top actuator with a moderate force to see if it will slip. You can push it toward the heater which I think is the HOT direction to see if you can move it to go hotter than it is. That should be the driver side. The metal rod does unsnap out of the arm into the heater box.

The white nylon arm on the bottom unsnaps off the rod also. Then you can move the arm into the heater box to see if it's going full hot.

If moving the arms toward the hot direction doesn't produce full heat, then you know your heater core is not giving enough heat.

[Tech II]

I disagree.....you shouldn't be pushing on actuators to make them move.....

First, when the vehicle gets to normal operating temp, feel the heater core hoses....they should approximately BOTH FEEL THE SAME, HOT....if one is much cooler than the other, there is an airpocket in the core, or try back flushing it......

The actuator for the passensger side......this looks like a dual zone, autotemp system.....the fact that the "temp" symbol is flashing, means there is a code set in the HVAC head.....those codes are specific to the HVAC and DON'T CORRESPOND to PCM codes....i.e., code 15 in the PCM means a problem in the CTS circuit, it does not mean the same in HVAC system...the code 15(don't have a manual on this) could mean something like a blend dooor problem(just a guess)....you need a tech II to read these codes....

If both heater core hoses are warm, and you want a temporary fix, disconnect the rod going to the passenger side temp door(pops out of the white retainer on the blend door lever)......then manually move the door lever until you get full heat......then tape it into the full hot postion with duct tape(love that stuff).....

[Pedantic.2012]

OK ... we allowed the car to warm up about 20 minutes. Heater hoses were both hot, one was slightly cooler than the other.

We then turned on the heat and of course hot on drivers side, cold on passengers side. We were afraid to disconnect the white plastic clip, didn't want to break it. But was able to manually move the top acuator arm towards the right and Voila we had heat, nice hot heat on the passengers side as well as the drivers side. We then shut off the car and restarted it and turned the heater back on. After about a minute the top acuator arm moved back towards the drivers side on its own and we lost heat on the passengers side and it was blowing cold once again.

Seems we do indeed have a bad acuator ... how the hell do you get that thing out ????

Oh yeah ... it's still codeing ... how do we get that to stop?

[HotZ28]

As mentioned, the flashing light after the ignition is turned on, indicates a fault in the system. Until the problem is corrected, the light will continue to flash. The system is out of calibration and can not recalibrate on it's own while the problem persist. In addition, if you were able to move the actuator arm manually, this is a clear sign the gear is broken. BTW, when the water pump was replaced, was the battery disconnected without first turning OFF the climate control while the engine was running?

[Pedantic.2012]

It could have been... But I'm thinking it was probably when I had the battery replaced as that is when the flashing started. We were well in the below zero temperatures and my battery failed so I had a new one installed. Chances are pretty good that I didn't turn the heat off when I arrived at the station and they just opened the hood and changed it. Problem? Flashing Cause?

[Tech II]

Like I said, the only way to read and clear the codes, is with a Tech II scan tool.....this tool also has the ability to command the actuators from full open to the full closed position.....this would test the actuator itself, and also show the position of the door via feedback.....

About the only thing that you can do is this......remove the key from the ignition....have nothing on.......remove the neg battery cable first.....then the positive cable......now join both cables together with a jumper for at least one minute....then reattach the pos first and then the negative cable.....SOMETIMES, this resets modules......worth a try....

Of course, if the actuator has set a code because it is bad, this won't help at all.......

[imidazol97]

Originally Posted by Pedantic.2012

Seems we do indeed have a bad acuator ... how the hell do you get that thing out ????

The plastic white piece has the metal rod with ridges on it snapped into it. It just unsnaps by pushing one way on the plastic and the other way on the wire to push it out of the press fit.

The actuator is held in place by two small bolts. I used a 1/4 " socket set. The rachet worked to loosen. Then I used just the little socket to finish removing the two screws. Be very careful not to drop them where they fall back toward the firewall!

New actuators are available from rockauto, box stores, etc.

If you are brave, you can study the movement of the axle arm on the actuator. Then take it apart and look inside. I used super glue on the gray hub axle after loosening the cracked gear slightly. I placed the gear so the movement against the driving gear didn't move in the area of the crack. I placed a drop of superglue, and pushed the axle and gear back into place. Be sure to note the axle has a prong outside that sits in a limited grove to restrict its range of motion--make sure that's in place first. Ask me how I know :grin.

A duct tape/bandaid fix is to unsnap the metal rod and just use ductage and a coat hanger to push the arm to the blend door into place. Then manipulate the coat hanger through the glovebox area, until you can get a replacement actuator in place.

For installing the actuator. I recommend a thread through the socket so it doesn't get lost toward the back. I usually put masking tape over the screw and the socket to hold the screw in place.