Air Conditioning -- Fire

[dk3333]

In Issue 169 of the Avanti Magazine page 15, Milt Yoder indicated that he was told that some Avantis had a problem with fires with A.C controls and that might be why the belt is missing on his Air Conditioning compressor. The belt is also missing on my 1981 Avanti. Is this a problem with my car such that I should not try to fix the air conditining. Is there a fix for the potential fire problem?

Thanks,

Don

[warren55]

First I've heard of it, but that doesn't mean there wasn't an issue. I use mine all the time and wouldn't want an Avanti without A/C.

[Gunslinger]

After all these years there's no real way of knowing why the a/c belts are off of any particular car...Avanti or other make. Maybe the compressor is locked up...maybe there's a leak and the owner removed the belt to keep from burning the compressor up...who knows without a complete testing of the system?

I'm not discounting whether Avantis have had a problem with the a/c switch having a fire potential...I just have never heard of one happening. What years...the original design or a later switch installed by Avanti Motors?

[sat65]

On my 84 there was a disconnected wire behind the AC controls. When I hooked it up the AC worked but the fan rehostat got VERY hot after a few minutes. I disconnected the wire again and haven't messed with it since.

[kboyd]

When I had the refrigerant in my 83's A/C system converted to R134a a couple of years ago, a problem developed that caused the magnetic clutch on the compressor to burn up. There was considerable smoke but thankfully no fire. The shop that changed the A/C refrigerant claimed the problem was the rheostat in the A/C temperature control was not passing enough current to properly engage the magnetic clutch on the compressor. This lack of current caused the compressor clutch to slip which resulted in overheating. They installed a relay that passed current directly from the battery to the compressor clutch when the system engages and thus far this has corrected the problem.

Since the A/C temperature control and fan switches did not work all that well to begin with, I replaced both with units I ordered from Nostalgic. Not sure I buy the slipping magnetic clutch explanation as the source of the clutch overheating problem since it turned out the shop failed to replace the A/C dryer when they purged the R12 refrigerant and it had become plugged with gunk from the solvent used to flush the A/C system. Since both repairs were done at once, I do not know which one was the actual problem. Maybe it was a combination but in any event, the A/C system is now working fine. My only complaint is the need to top up the R134a refrigerant charge every spring but it will hold through the summer. I am under the impression this is a common complaint with R12 to R134a refrigerant conversions if you do not also replace the rubber hoses. In any event, topping up the R134a refrigerant charge is a relatively simple procedure that I do myself.

Given the glass area, Avanti's can be rather warm in the summer without A/C so you might want to go ahead and get your system working though given the age of the components, if I had it to do over again I would replace the A/C temperature control and fan switches before I had the system recharged. Given that your A/C system is currently disconnected, you will probably need to replace the A/C compressor since the axis seals on the existing compressor will probably leak when you recharge the system. Remanufactured GM A6 A/C compressors are reasonably priced and available at most auto parts stores. Also plan on replacing the inline refrigerant dryer.

Good luck.

[boogieman]

Luckily no fire in my '79. I had the compressor replaced and have 2-40# containers of R12 to recharge my system.

New compressor, new drier, new Freon, and I'm good to go.

I'm told to change over to 134 requires a complete new system with hoses and fittings compatible

with the 134 refrigerant to function properly, or for more than one summer at a time.

Has to do with the molecule size of the 134 being much smaller and migrating through the hoses and connections.

Makes sense to me anyway.

[Jim78]

"The shop that changed the A/C refrigerant claimed the problem was the rheostat in the A/C temperature control was not passing enough current to properly engage the magnetic clutch on the compressor. This lack of current caused the compressor clutch to slip which resulted in overheating. They installed a relay that passed current directly from the battery to the compressor clutch when the system engages and thus far this has corrected the problem."

This sounds like the wires were incorrectly installed on the controls. The rheostat powers the yellow wire to the variable speed fan motor. The brown goes to the clutch from the thermostatic switch. The black is the power.

.

Edited March 21, 2015 by Jim78

[unclemiltie]

In Issue 169 of the Avanti Magazine page 15, Milt Yoder indicated that he was told that some Avantis had a problem with fires with A.C controls and that might be why the belt is missing on his Air Conditioning compressor. The belt is also missing on my 1981 Avanti. Is this a problem with my car such that I should not try to fix the air conditining. Is there a fix for the potential fire problem?

Thanks,

Don

Dan Booth is the one that warned me of the AC issues

[drexlog]

A few years ago I bought a "barn find" 87 with (well several) wiring problems and the air conditioner was not hooked up. When I got around to finally hooking it up, I looked at the Stude Avanti manual, I hooked up the air conditioner the way the book said and sure enough, the goofy thing overheated. After everything cooled down I reversed the wires and everything worked fine (well at least for awhile...had to get a new compressor). GM parts fit great as replacements. Looking back at the entire thing, I think it was an issue of me either reading the manual wrong or the manual was just wrong (which I sort of doubt).

[plwindish]

I rely on a competent radiator and ac repair shop to do the work on my 76. I've had issues with being low on freon and had to replace a drier, but have had no electrical issues with it's ac controls.