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A/C Compressor Toast?

7K views 10 replies 7 participants last post by  Stella501 
#1 ·
So today went to use the AC for the first time since last summer and it seemed to not be blowing that cold but all was running okay... meaning compressor was cycling on and off as needed.

Swung by Autozone and picked up one of those refrig fill cans, which I also did last year, went home, and proceeded to charge the system.

I let the car run for a bit to make sure all was okay and within maybe 5 min, I started to smell a burning smell, looked over at the compressor, and there was smoke coming out of it, so I turned off the car. Let it settle down a bit and turned the car back on again to watch the compressor to make sure the clutch was engaging and noticed that it wasn't acting normal, or at least I didn't think so.

When the compressor first cycles on, the center spins much slower than normal, then after a few seconds, it will spin at normal speed. Every time it cycles on and off, it does the same thing, slow spin, then normal. In addition, the compressor was making some weird noises, almost like it was straining. From reading around, it sounds like the system might be overfilled, but why would it make the compressor smoke?

Anything I can do first before thinking about replacing it?

Thank You.
 
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#2 ·
Over filled. It creates too much back pressure and the compressor has to work harder. The smoke and clutch operation is showing that the compressor is under such a heavy load, it's slipping. You might not have killed it, but you need to take it somewhere that has the equipment to service it properly. It's odd because the pressure sensor "should" turn the compressor off if there's too little or too much pressure.
 
#3 ·
I second that, these cars have to be charged almost perfectly, very hard to do without pulling a vacuum and adding the exact amount. 2 ounces over and you get the lock up. Also if you add a can that has 2 oz of oil, too much oil and it can't flow fast enough to get thru the expansion valve. And I hope you bought plain old fashioned R134a, no oil or stop leak. The sealer cures into hard plastic when it hits air ( like when it hits a pin hole, and that's how it works) or any moisture inside the system. Oh, how you add the right amount, 23 oz on my 97, is use a postage scale to weigh the can and do the math. Ounces is weight not volume.
 
#6 ·
I have to check the can again but I think I did buy the stop leak can. I'm honestly not sure at this point because I picked up about 3 or 4 cans in a an attempt to choose which to buy. I will check but I see your concern.
 
#4 ·
You can slowly empty some refrigerant out of the low side port using the hose your can came with, until it cycles properly. Then take it and get it vacuumed and refilled with the correct amount (or just do step 2 and save the environment)

If the compressor was as you say "cycling on and off as needed", why did think you needed add more refrigerant? Was it cycling on, then off quickly, or would it run for a while before it dropped out?

The smoking compressor could be a result of an overcharge, but it could mean that the air gap between the clutch and the pulley has grown. The electromagnetic coil and spring setup can only pull the clutch a short distance...like .020". If your air gap has grown in excess of .020", you may need to remove the clutch and remove a shim to close up the air gap.
 
#7 ·
If the compressor was as you say "cycling on and off as needed", why did think you needed add more refrigerant? Was it cycling on, then off quickly, or would it run for a while before it dropped out?
Thought it needed more fluid because the air coming out was not very cold at all. It was cool, but not cold as usual and it wasn't even that hot... maybe 82F.
 
#10 ·
This is a really good thread, maybe it could get moved to the How To section. I should have elaborated a bit more. First, get the plain ol' R134. Get a charge hose that has a gauge on it. So, your AC is a bit warm and/or smells like a wet dog. A quick check is put the AC on, fan on high, fresh air, let the car idle a couple of minutes. Touch the low side pipe where it goes into the compressor, it should be cold and sweating condensation. If it is, check the temperature door adjustment, not hard, it's on the passenger side of the heater, you might need to pull the glove box. If it's cool, put the can on the hose, but don't crack into it yet. A proper charge on an 80 deg day will read 30ish psi. If you rev it up a bit to 1200, it should drop to 25. If the charge is low at idle you'll see 25, then it will drop to about 20, then the compressor shuts off. Also if you rev it a bit, the pressure drops right away to 20 and the compressor kicks off. And takes a while to come back on. You can charge it by the gauge. Make sure the can is upright, this is called vapor charging. It's the slow way to do this, but as the AC cycles it will pull in refrigerant slowly. Shut the valve off once a minute and see how cold the line is and how fast the compressor cycles (it will be slower now) and the gauge will be reading 30-32 while the compressor is on. If you hold the can upside down, liquid goes into the system, and it's overcharged in no time. Now if you don't mind pain, or own a contact thermometer, the high side should be at around 200 psi which translates to about 140 degrees between the compressor and the condenser. (think DeflateGate under your hood) . If anyone reads this and has some experience, it's a few rules of thumb without a trip to the shop. If you got feeler guages, .015 to .020 is good. If the clutch is worn, these are Sanden compressors, all you need are Harbour Freight snap ring pliers and simple tools, they are easy to change, no need to dump the Freezone....Also make sure the coil has a good ground, and is getting within a half volt of battery voltage, along with the gap a simple electrical issue like weak ground, toasty relay or corroded fuse can make the clutch not pull in hard enough. HTH S PS Ac stop leaks aren't as notorius as a few years ago, don't lose any sleep if you did put some in, the problem arises if you open the system up to do a seal or condenser (If you do a condenser go dealer or World Pac they fit right) the sealer hardens up when the air hits it. You may wind up doing the expansion valve.
 
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