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Buick LeSabre Heating / Cooling

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  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    The removal for the radio/HVAC control is that the plastic wood pieces pull out of the dash with metal pressure fittings. Just give a good pull.

    Then the front of the dash comes off with a screw in each of the air vent openings at the bottom after you remove the movable air deflectors. Do not drop the screws down the air openings. This is called the trim panel. My 98 FSM only shows the 4 screws holding it. There are either more screws under or there are press fit friction clips.

    I am not sure this is a good set of instructions. I have never had that panel off on my car.

    I also think that usually the problem with the controls is the programmer box under the dash on teh corner of the heater box or one of the two electrical fuses.

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  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    edited June 2013
    >the blower module is bad

    Was that the blower control module? It's the equivalent of the resistors that change speeds in the regular control setup.

    the Blower Control Module is where the power cables from the blower motor lead up on top of the heater duct the motor sits in. The module is cooled by the air just like the resistors are.

    If it's bad, there is no fan, but everything else works okay.

    The relay center above it is held by two screws and can be lifted slightly to give access room to the two screws holding the module in.

    Remove the negative battery cable before moving the relay center with its fuses and relays.

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  • My 2002 lesabre has starting overheating on me. The first time my mechanic said it was this tube that runs through the engine block. He said if that is rusted inside it will make it overheat so he changed the external tube and it stayed normal for like two weeks. So then it would only overheat when sitting too long ar a light vut as soon as i drive itll drop a few noches, not completley but out of danger. So, i changed thermostats, hoses, put only coolant and it worked for like a week, temperature stayed below danger but above normal. Now it completley overheats to the point where the car has cut off. Is my problem the waterpump? there is no water leaking. HELP!  :)
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    Take a look at the color of the engine oil on the dipstick. If it's a brown, milkshake color, your coolant may be getting into the engine oil. That's fatal if it has gone on for a while.

    I don't understand what the mechanic did. But the most common problem will be the gasket under the metal lower intake manifold and the heads has deteriorated and is allowing a leak into the engine air intake and the oil pan. That may explain the stalling because the coolant causes misfiring in the cylinders.

    A second problem area might be the intake manifold that's plastic where it meets with the metal throttle body that controls the air intake and volume. That gasket can leak.

    A third area might be the EGR internal port which is hard plastic has deteriorated with heat--not as likely after 1999.

    A fourth problem might be not the above but that the coolant is goopy if someone added regular green antifreeze to the original orange DexCool. That may be blocking some of the coolant flow through the radiator.

    You need to find a good mechanic who knows these cars. A dealer may be your best bet for an analysis of what the problem is, despite their higher cost. You may be spending money as well as time with damage occurring at a poor local mechanic.

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  • shildebrshildebr Posts: 1
    Is there a chqnce you still have these pictures and how u fixed this issue. This is the exact issue i am having with my 1999 buick lesabre. Thanks for ur help.
  • I had to replace my battery and now my ac is not working. Air will only blow through the defroster and it doesn't get very cold. I have had my car looked at and was told that my a/c unit is working fine and it is probably an actuator but now sure how to decide which actuator to buy. I have automatic ac with temperature display but not dual controls. Please help...
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    What year is your leSabre?

    When there is no vacuum, the system should go to defroster for safety.

    But on 1999 and prior, there also is a problem with operation of the actuator for the door that blocks the defroster and makes air come out the dash vent.

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  • bhoppbhopp Posts: 5
    2002 lesaber heat blows cold unless temp set at max 90 it is a limited w/dual control
  • bhoppbhopp Posts: 5
    where is temp sensor for heating system dual control digital system
  • My 99 Buick Lesabre AC doesn't blow through vents. It only blows out the defrost and floor. It works on all fan speeds. No matter what air flow position I select on the Ac head unit it will only blow out the defrost and floor. I have done a lot of reading on this problem and thought several times I was close to solving the problem with disappointing results. Here is what I have done to this point. I have replaced the AC head unit twice, what they call the Air Mix Actuator and the AC programmer. (All parts from local salvage yard). The vacuum line leading in from the fire wall has been vacuum tested. When I first turn my key on the 2 levers of the doors move to the right and then back to the left. If I change my temperature on the head unit to warm then the 2 levers move to the right and I have heat. So I am assuming the doors are functioning properly(??) But like I said no matter what air flow selection I choose on the AC head unit I only get air flow from the defrost and floor. Nothing comes out the vents. I am at a loss. Can someone please help? FYI... I had the same problem on a 94 Lesabre and I change the head unit and the problem was solved for about a year. Then it would from time to time just blow out the defrost and floor. You could just be driving down the road and it would switch back to the vents. Makes me wonder if the head unit was the whole culprit on the 94 or not? I've sold the 94 so it is not an issue now. I thought I would mention my 94 problem just so you know my frustration with Lesabre AC issues. Once again CAN someone please help me?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    If the other vacuum controls move correctly when set on floor/windshield, and you are sure you have correct vacuum with no leaks at the storage tank behind the headlight, and you can move a line off the floor control diaphragm on the driver side and put it on the diaphragm for the upper doors (blue line), then you have a problem with this sucking shut.

    http://i86.photobucket.com/albums/k110/imidazol97/DSC03124.jpg

    You can cut it off from the vacuum lines and slide vacuum line over the tubes (Oreilly's sells it by the foot or in boxes). Connect the correct color from the inner part of the programmer box to the color on the outside--they are not all the same.

    Programmer sits on corner of heater box.

    http://i86.photobucket.com/albums/k110/imidazol97/HeaterCore1-1.jpg

    You can reach all this by removing the sound shield under the dash and removing the glovebox door at the hinge.

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  • i have 97 buick lesabre. last winter, the heater worked awesome, not a problem. so far this winter, the heater blows cold air, even after letting the car run for 10-15 minutes. the airflow will start going to warm after driving it for a little bit, but not much (in a 30mph zone). hopping on the freeway, the heater works just fine, but when sitting at a stop sign, or a stop light, it starts blowing cold again. any ideas?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    edited November 2013
    I assume it's the manual control heater and the actuator for the temperature is working right. See last paragraph.

    Your car may have a thermostat that is not closing completely when cold or opening too early. After 5 minutes with a cold engine, the upper hose should still be cold while the heater hoses are warm and hot. You should be able to feel the thermostat open when the coolant gets to 195 as shown on the dash gauge, by the hot water coming into the upper hose in slow spurts and warming it some. The thermostat may open slowly and just the bottom of the hose gets warm at first. After 10 minutes or so, the upper hose should be too hot to hold for more than a few seconds unless your hands are really toughened up from being used to hot things.

    You might have low coolant level in the radiator--have to take the cap off when cool to see if there is coolant up to the cap level. Can NOT check just the level in the plastic reservoir. But that usually has a couple other symptoms.

    Your coolant may be old and clogging the heater core lowering the flow rate. If you are careful you can check the temperature of the two lines into the firewall behind the engine. Be careful of the moving belt at the alternator. After the engine and car have been warmed up, with the heater blower on high the temperature of the one metal tube should be some cooler than the other one. But both should be hot. If you turn the fan speed on low and retest, the tubes should be nearer in temp due to the water in the heater core not being cooled as much by the air.

    Having someone run the engine at 1500 rpm or more for a minute before testing should improve the temperature of the out hose making it closer to the input temperature.

    If the flow in the radiator is partly blocked, you can have the cooling system cleaned with a cleaner to try to pick up some of the gunk in the heater. The better solution is to take off the rubber tubes at the engine end and try to flush the heater core with light water pressure in both directions.

    A remote possibility is a water pump.

    The electric actuator on top of the heater box pushes a white plastic arm and a metal rod to move the temperature blend door. That actuator may be slipping and not pushing the rod all the way to the hot side. You can take off 3 screws and a couple taps on the firewall to remove the plastic panel under the dash. Take off the glovebox door for easier access--7 screws across the bottom hinge. You can try to move the actuator with a gentle push. If it moves, the inside axle is slipping due to a cracked gear. OR you can watch it move as you change the temp setting with the key ON to see which way it goes for HOT, and then try to push it further and see if you get more heater with the engine running in that position. If the actuator is going full hot, with a hot engine running at 40 or more the air coming out the vents should be so hot you can't hold your hands there.

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  • jdunawayjdunaway Posts: 4

    Hello. First let me say what you are providing is awesome !! I have read many of your posts and the answers are intelligent and insightful. So I am hopeful you can help me locate my problem. My friend has a 95 Buick Lasbre. Complained of low heat. I know a little about a lot and I love to help so here I am lol. I noticed the coolant looked rough and she said she can't remember it ever being changed. So that's the first thing I decided to do. Never over-heated and all of the manual controls worked well so I figured it was a good start. After flushing and draining 3 times I added Prestone's mix and let it warm up. Had awesome heat. On the drive back to her house it all dropped out and went right back to blowing cold air. I opened the hood and felt the upper radiator hose. Slightly warm but nowhere near what it should be. I noticed both fans were running. I let it sit and idle for about 15 mins and the air was still cold. Fans still running. Hoses still cold. I didn't think to reach back and feel the heater hose lines. It is 6 degrees out there and night time. Should those fans be running when the water temp isn't hot ? It only has a temp light so I do not know what the engine temp was :( Tomorrow I will dive deeper. Any advice would be awesome. BTW, sliding the cold/hot slider works well, switching from defrost to floor, to blend works well.

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    edited January 29

    @jdunaway said: I opened the hood and felt the upper radiator hose. Slightly warm but nowhere near what it should be. I noticed both fans were running. I let it sit and idle for about 15 mins and the air was still cold. Fans still running. Hoses still cold. I didn't think to reach back and feel the heater hose lines. It is 6 degrees out there and night time. Should those fans be running when the water temp isn't hot ? It only has a temp light so I do not know what the engine temp was :

    Check the coolant level in the radiator--not the reservoir--tomorrow. You may not have gotten all the air out. Fill radiator with coolant with engine running. Then rev engine, either yourself with the throttle on the engine or have someone hold it at 1500 or so and add coolant then put on cap while revving. Drive car until it should be fully warm. The fans should not be running. I suspect you were running hot. They may come on at 217 or so. With 6 deg outside, it was easy for the low coolant to keep below emergency temperature.

    After upper radiator hose is hot with coolant leaving engine through thermostat, run engine at 2500 for 10 sec or so then idle. Repeat 4 times. That should move air out of heater core. Then last open the little screw on top of the thermostat housing on upper radiator hose on engine to let out the air. You can do this with engine off while still hot. Open screw until air bubbles out and you get coolant.

    Did you replace the thermostat? Should have done that as prevention. They are good for a limited number of cycles; then you are riding on borrowed time. I recommend Stant Superstat at 7.99 at advance auto parts and a new rubber o-ring that slips over the metal edge of the thermostat for 3.50 or so. If you are going to do the thermostat, drain out about a gallon of coolant before taking off the thermostat housing.

    After flushing and draining 3 times I added Prestone's mix and let it warm up.

    If you rinsed with plain water and then added 50/50 Prestone, you do not have enough antifreeze, in my opinion. The volume is about 13 quarts for the system. If you're rinsed and drained 3 times, you have little left of the original coolants. If you added 50/50 Prestone that's not 7 quarts of Prestone. Each gallon on had 2 quarts of pure Prestone.

    Did you open the drain on the bottom of the radiator? That may have drained more plain water out. My method was to rinse and drain after warm up, 2 or 3 times. Then add the 7 quarts. Then add more water if needed. That way I knew the 6-7 quarts was in there for freeze protection.

    Get a gauge that measures the antifreeze temperature--even if just one of the little floating ball devices.

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  • jdunawayjdunaway Posts: 4

    I'll be replacing the thermostat later today. Like you said, I figured it's a good thing to do and easy so might as well. I did remove the lower radiator hose and drained that way. The petcock always seems to be a problem so I didn't even bother with it. I have already did as you described by running the engine up to 2500 and then idle 4 times and removed air via the set screw on the thermostat housing. I had awesome heat for around 30 mins or so while it was idling in the garage. When I took it for a drive is when the heat went suddenly cold and never returned. The top radiator hose was barely warm and those fans wouldn't shut off. Is it possible that the thermo switch for the fans gets stuck on ?

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,704
    edited January 29

    @jdunaway said: Is it possible that the thermo switch for the fans gets stuck on ?

    When you start the engine cold are the fans on? That would be true with a stuck relay. I don't suppose you have a scanner for the cars that's more than a code scanner: I have a scanner that shows the engine temperature that the computer is seeing.

    I had awesome heat for around 30 mins or so while it was idling in the garage. When I took it for a drive is when the heat went suddenly cold and never returned.

    That sounds like air in the heater again. What's the coolant level in radiator? If it dropped again you may have gaskets leaking coolant. That's a Series I engine though, isn't it. Or you have a glob of something that moved and blocked the heater core. See what happens after thermostat replacement. And do testing after idling to warm up of heater hoses. Also check that the thermostat starts releasing hot water after getting up to temp; you'll feel the bottom of upper hose get warm first as a little coolant is released. Then more until the whole hose is hot.

    The top radiator hose was barely warm and those fans wouldn't shut off.

    Are you in a climate where the air temp gets above 45-50 deg? And you have the HVAC controls set on something where the AC is turned on automatically--turn on the Vent button and see if fans turn off after a minute.

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  • jdunawayjdunaway Posts: 4
    edited January 29

    It's around 10 degrees outside now. Last night it was 6 and the fans were on during idle while the radiator hoses were cold. I'm not sure if they were on while it was cold and a fresh start up. I'm gonna go get the car now and run some more tests. Also replace the thermostat. I'll burp the system again and add fluid while revving the engine up. I'll also check the heater core hoses after it gets hot and see what I find. I'll report back in a few hours. Thank you for your responses !! :)

  • jdunawayjdunaway Posts: 4

    Well I cleaned the relay connections, burped the system, new thermostat and gasket, and filled the system while holding it at 2000 rpm. All seems well. :)

  • Needing some help for my 1995 Buick Lesabre. When turning on my heater or AC I can hear the blower motor running at all of the different speeds (I have the manual control with slide lever) including high speed but I hardly have any air coming out of the vents. I can switch between defrost, vent, floor and the air is redirecting where it should go and is very warm since it's cold outside, but there is hardly any airflow. I turn on the recirculate and still only have minimal airflow out of the vents when in high position. Have replaced blower motor and tried a different electronic control module inside the car; took apart the vents on outside of the car to make sure they weren't plugged; have used my DMM to make sure all fuses are good and that I have voltage. Not sure what else to try. This problem occurred literally overnight the airflow was fine one day and not the next. Any help is appreciated.

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