2000 Lesabre Has No Heat

Is it the fan that's not working or just the heat?

https://modulemaster.com/rebuilds/shop/comfort/climate-controls/buick-regal-1999/

Just the heat. Fan works fine.

I would ask the 'modulemaster guy' he welcomes questions, and probably has more experience in these heaters than anyone....but he's closed today for Memorial Day......

Whoa, whoa whoa.

Stop replacing parts suggested by the parts store guy. Or worse yet, has a ‘mechanic’ been engaged to swap perfectly good parts for new perfectly good parts by the hour?

Well said!!

We all miss Click and Clack, the Tappet brothers!

Google, "2000 Lesabre Has No Heat". Your best advice will be found there.

I agree with Doorman, search or take it to the man!

Googled it numerous times and keep coming up with the same answers; "replace 'all the parts that I have already replaced'"

OK, That's all I can offer.

Good luck.

It sounds like the cabin environmental control system on this 18+ year old vehicle has freaked out. You've already replaced so many parts that are usually the culprits I suspect the wiring harness or computer control might be your culprit.

I have a recollection of replacing a vacuum operated antifreeze fluid valve threaded into the intake manifold on the early 1990's era V-6 because the first replacement unit failed after only a year and I had to replace it a 2nd time.

Would GM still be doing that 7-8 years later?

"As far as the AC compressor always running that was also a common problem."

I'm not sure the AC compressor always running is a problem.

I can't speak authoritatively to new GM systems, but my '72 Vette compressor ran all the time and a suction throttling valve was used to control refrigerant flow.

I believe that is still common practice.

I know that newer GM vehicles don't run the compressor all the time. The compressor is an R4 (not as long and larger diameter). These are known to be pretty robust compressors.

Lyn, your 1972 Vette should have an A6 compressor, which is the long one with the smaller diameter. It most likely has the POA valve, which controls the refrigeration. Your compressor should only be on while the AC is on. Your AC clutch will disengage when the AC is turned off. Otherwise your AC clutch is engaged and the compressors will be controlled by the POA valve.

GA!

There will be a solenoid valve, mechanical valve or other thermally controlled valve in line somewhere, find and check that

https://www.youtube.com/watch?v=DO_SH-RTvvo

I am a rather simplistic sort. Is the heater core getting hot when it is supposed to?

Before you start your diagnosis of a problem, you need to start a series of steps and to gather some tools and information.

1. Vehicle electrical schematic.

2. Volt / ohm meter.

3. Vacuum pump / gauge.

4. Notebook - pen and paper to make notation on what the system is doing and is not doing.

5. Air compressor.

6. Pan of water, stove and thermometer.

7. Diagnosis flow chart.

The first step is a functional test. If your control system is electrical or electronic then this means that all control systems are operated via solenoids and / or servo motors. If your control system is non - electrical, then this means that everything is controlled by cables and linkages. Some systems use a combination of both.

Next, get out your electrical schematic, if only wiring is coming into your control switch and only wiring is going out of your control switch, then all of of your system controls are electrically operated.

You said that you replaced : heater core, radiator and thermostat.

1. Check heater core : generally the heater core will fail due to two reasons, first, the core is leaking ( observation ) you smell coolant, you see coolant dripping onto the passenger floor well or see coolant leaking onto ground beneath vehicle. The core is clogged with minerals or scale. If the core is leaking, you can test it by sealing the inlet and outlet and putting it into a bucket of water. If you see bubbles, then the core is leaking, you can also pressurize it with the air compressor with about 20 psi. Bubbles equals a leak, no bubbles, no leak. You can clean the core using two methods : a. Degreaser and nylon brush on the outside. b. Plug one end of core, inlet or outlet, pour white vinegar into core and allow to sit overnight, drain and flush with water the next day.

This same method can be applied to the radiator.

How to check thermostat : put thermostat into a pan of water, when the water is cool, the thermostat will be closed ( observation ) . Heat the water in the pan, at approximately 104* - 110* the thermostat will start to open ( observation )

If the core, radiator and thermostat pass these tests, then these parts are good and do not have to be replaced, if not, only replace the parts as required.

Using the flow chart : Operate switch - if ( a ) and ( b ) function correctly, go to ( c ) . If ( a ) does not function correctly, correct problem with ( a ) . If ( a ) and ( b ) function correctly, to to ( c ) .

In diagnosing any piece of equipment, you need to follow in a logical order : observation, system check, flow chart, component check, repair or replace. Then repeat the order.

Diagnosis of a system in a logical order allows three things : 1. resolve the issue quickly. 2. Only replace or repair those areas required. 3. Keep repair costs within budget.

lots of words.. lets see if i can get rid of some...

heater core leak,, small leak= still hot.. Large lead= water all over floor.. bigger problem.. didn't mention so we can delete this.

no need to test the thermostat because hot water is bypassed to heater core before thermostat.. which is why you get faster heat. so you can put your pan away as well as your hotplate.

your test for electrical continuity won't do you any good because these heater/cooling systems run on a vacuum system. so we can put your multi-meter away too.. as well as your electrical diagram.

Sounds to me like a cracked head or leaking head gasket. what happens is gas gets trapped in the upper part of the head where water usually circulates and then goes to the heater core. It is done this way so that heater core gets hot water fast. But when there is a big gas bubble that restricts water from flowing to the small 1" hose, the result is no heat. Engine can usually operate with no apparent issues unless a heavy load is on the engine such as driving up a mountain and then you may see the engine over heat. You can also verify this by running the auto with the radiator cap off ( from the start) and you will see bubbles continue while the engine is running, depending on how bad. milky oil is not always visible depending on where the crack is located.

I replaced the head and gasket and sent the block out to be checked. all good there. As for a vacuum leak, all of the controls are mechanical. there is no vacuum involved in the HVAC system. I even have the guys at Buick scratching their heads.

I can’t watch any more of this. Sorry.

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did you try running the engine? there will be no heat unless the engine is running..

Don't forget to check the coolant if it is brown or gunked up.

Hold on one minute! You own a 2000 Buick LeSabre which is worth about $500 or so - 1000 on a really good day.

You've replaced both heads, new head gaskets and pulled the block and had it checked.

You've replaced a lot of AC parts

Your HVAC is still having trouble.

Please remember that you have an 18 year old Buick. Is it worth all this effort? Or do you stop the bleeding and get rid of the car?

I believe the best thing to do is punt. Sell the car or take it to Carmax. Then go out and buy a Toyota Camry or Honda Accord They're that good!

Well I found and replaced the correct part, FINALLY! Got a new car.

I'm glad to hear. Sometimes we try to fix something and we lose sight of the whole pictures. Seeing the forest from the trees!

Congratulations and I wish you years of enjoyment.

Just about every engineer I have ever met does that!!

My saving grace on this subject is my Scottish blood, it prevents me from giving out too much money.....it also "pushes" me into cheap ways of checking what is wrong!

A good nights sleep on the problem is also a definite help.

In this case, I would have guessed that it was fixable, probably a simple part....like that valve someone mentioned.

I would have removed it and cleaned and lubricated it, checked out is function as far as possible, then put it back in. If the problem was fixed, I would have bought a new one and installed it. End of story!

I think we're all guilty of it. I've spent (wasted) hours working on things that weren't worth the effort, but I was "stuck" on the project and I didn't want to give in. At times, I know I can fix something, so I do it, but it would've been less expensive and saved a lot of time if I would've just replaced the item.

I've also noticed that many products are no longer repairable, because the parts aren't available. Or the seams are glued together, so one would have to cut the item apart, repair, then reglue it back together - most times you could never get it to look as good as the original. Our disposable society!

Of note, a few years ago, I was replacing the outlets in one of my houses. The house was built in the late 50's to early 60's and a few of the outlets were original. When I took a closer look, they were not glued together, but instead had been screwed together. I took one apart and I found that they were made to be repaired. As a science minded guy, I took a newer, broken outlet apart and made note of the differences in quality. The old outlet was made with better parts and was "heavy duty" compared with the disposable unit.

Good for you!

My "heads up" is always what will it cost to repair versus what a new one will cost!