2002 Lesabre no heat, engine at normal temp, coolant at proper level

ekto

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lesabre, century
Just in time for the cold weather! I went for a drive yesterday and turned on the heat, it blew cold air with the slider turned all the way up. the temp gauge showed normal, the overflow tank was full ( although I will go out after posting this and check the radiator) . I don't think the coolant is low, but we'll see.
Another point- The previous owner said that sometimes she would hear what sounded like running water coming from under the dashboard. I heard it once or twice too.

It sounds like something to do with the vents but I would like to have some information before I go tearing the blower system apart. I hate working under dashboards.
Another issue- Recently I was driving along and the "traction off" light and the "ABS" lights came on. There were no problems with the car, so I drove to where I was going. After stopping and starting the car, and pushing the traction button, everything went back to normal, for 45 miles. So now when I drive 45 miles, the lights come on. Does anybody have a clue?

Also- Does anyone know where I can get good technical info for my cars without spending a whole lot of money? Especially wiring diagrams. In the past I used to get the Hayne's manuals, but I havent seen them in a while. I don;t do much repair (only when necessary) and it always is a pain, and sometimes confusing trying to figure if those you tubers know more than you do.
Well, thanks for listening, I hope someone can help me out, it's starting to get cold! Thanks
 

MelsRegal

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The running water sound is do to air in the system.
The car may have a non-functioning heater control valve
 

imidazol97

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Are both radiator hoses hot with the blower running on high?

If so, See if your radiator is full to the cap. Then with the engine completely warmed up, run the engine at 2500 for 10-15 seconds, let it idle for 30 seconds, and repeat 4 times. This is supposed to help push the air out of the heater core. There is a bleeder screw on the thermostat housing to let some air out that might be trapped there.

I have a driveway sloping up some, so I would put the firewall lower than the radiator when I did the revving to make it "easier" for the air to escape.

The air and water is the source of the sound.

Some recommend having a second person hold the engine at 1500-2000 rpm while you pour coolant into the radiator opening if you find the level is a little low. When you rev the engine, the level in the radiator goes down, so filling it that way and putting the cap on before letting the engine slow gets as much coolant in as possible.
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imidazol97

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If the radiator hoses are both hot indicating good flow of water, you might have a bad temperature door control motor.

If you take off the plastic panel under the dash, you should be able to identify where the motor is and watch it
to see if it operates when you change the temperature on the dash. It sounds like you have the single door rather than
the dual control with two temp motors.

You should be able to see the axle on the motor rotate when changing the temp setting if it's a blend door problem.
 

FJM

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2000 Lesabre Custom
wow....I have a 2000 LeSabre with the exact same issue (except the traction control). I'm going to try all recommendation. Thanks
What was your final results EKTO?
 

FJM

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2000 Lesabre Custom
If the radiator hoses are both hot indicating good flow of water, you might have a bad temperature door control motor.

If you take off the plastic panel under the dash, you should be able to identify where the motor is and watch it
to see if it operates when you change the temperature on the dash. It sounds like you have the single door rather than
the dual control with two temp motors.

You should be able to see the axle on the motor rotate when changing the temp setting if it's a blend door problem.
Both my radiator hoses get warm not to hot, the 2 hoses going into the heater are hot!. I'm not sure where to go from here? Frustrating!
I will check the temp door control motor next.

I did not mention that I did a back flush on the heater coil and got some nasty stuff out. I tryed to refill the radiator but it would not take much.
The temp gauge goes right to the middle where it has always gone.
As you can see I'm all over the place. I'm to the point now that I dont want the car to over heat. Suggestions please
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imidazol97

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In my quote, my first sentence that should have read "if both heater hoses are hot..."

You say yours are evenly hot with the heater fan motor on HI. The exit hose might be a little
cooler because the water loses some heat to the air inside the heater box.

If your radiator hose at the top doesn't stay cool when the car is cold started, and then start
to warm up after the temp gauge starts its move up, you need to think about the thermostat.

The thermostat should hold closed until 185 or so. All the hot water should be circulating through the
heater hoses and (I believe) a return tube into the block.

After idling for 8-10 minutes, you should start feeling the upper radiator hose start to have warm water
in it as the thermostat opens some because the water under it in the block is heating up. So it will
open slightly and some cold water reeturning from the bottom of the radiator will go into the block.

After a short drive or idling quite a while, the upper hose should be too hot to hold your hand on
for more than a few seconds, unless your hands are very tought. LOL. It should be up to 190 and more
the temp where the thermostat is wide open.

How old is the thermostat? If replaced, was the rubber ring that it sits in the middle of replace? If the
edge of the thermostat plate is not in the groove in the middle of the rubber ring, water can go
around.
 

FJM

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Frederick, MD
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2000 Lesabre Custom
I do not know how old the thermostat is. The hoses are working though as you describe. The back 2 hoses (in and out of the heater coil are very hot).
I lost a lot of fluid when I disconnect the hoses from the water pump (behind the alternator). for the back wash (got some nasty stuff out of there). I filled up what I could directly thru the radiator cap but it did take alot..so it seems. The reservoir is where it's suppose to be. I know it has to be low but no fliud seem to be getting to the engine which makes me thing the Thermostat is not opening. The heater coil only has water in it from the back wash...
Thermostat?
I'm gonna let it Idle for a while and see what happens.

You previously mentioned a temperature door control motor. Do you mean blended door actuator?

Thanks i
 

Homer Jay

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2001 LeSabre
To ensure proper circulation,bleed the system of possible air. There's a bleed port on top of the thermostat water outlet.
1601927342764.png
 

FJM

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Frederick, MD
Buick Ownership
2000 Lesabre Custom
I wanted to pass along....my heat was suddenly intermittent working then suddenly nothing......after back flushing the heater core, replacing the thermostat it turns out the culprit was the heater/ac blend door actuator located behind the glovebox (2 screws, pull firmly, disconnect the light) and the glovebox is removed. no need to remove glovebox door). The actuator is to the left fooking forward. It took all of 5 min to change.
Winter suddenly doesn't look so terrible for my commute:)
Thanks everyone for passing on your wealth of knowledge to this rookie!
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imidazol97

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Yes. The blend door mixes air that bypasses the heater core with that which goes through the heater core to get the
wanted temperature. Many people confuse the mode with the blend, so I usually call it the temperature control
door because that's what it does.

You previously mentioned a temperature door control motor. Do you mean blended door actuator?

Thanks i
 
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