The following comes directly from my husband Joel. You can reply as if you were talking directly to him and I will send him a link to this thread. If he has any more questions I'll post them.

Thanks! :seeya
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We went on a trip today and the A/c was working fine. On the way back, we stopped for gas and got back on the road. About a mile or so down the road we turned A/C back on again. We notice burning smell and smoke coming form engine compartment. We pulled over and
turned off car to investigate. We noticed that smoke was originating from front of A/C compressor assembly where the pully is connected by the A/C clutch assembly. Smoke and a bad smell originated from rubber burning.
We turned back on vehicle without A/C on, and there was no smoke or burning rubber. Turned back on A/C unit and smoke appeared again along with smell of burning rubber. Auxillary belt seemed fine with no melted spots. I noticed that when A/C was running that the pully would turn freely but clutch didn't seem to engage, it may have been trying a little though which is what I believed caused the friction and burning
since it would not rotate at the same speed as the pulley.

Could anyone give insight and suggestions into this problem?

Also how about a crash course on the operation of the A/C clutch assembly in relation to the A/C compressor and pully around the clutch?

Lastly, if it is the A/C clutch assembly how hard and how long would it take to replace it?

 

AC101....first what year is the car. The compressor clutch assembly can be replaced if it has seized or is not engaging due to loss of clutch contact surface...but usually it is due to a seizing of the compressor components internally due to loss of lubrication. most compressors only have about 6 oz. of oil in them and that can circulate in the system. if and when any get stuck in the evaporator due to lower refrigerent velocity in the evap then the pump will still want to fill up the cylinder of the a/c compressor and it sucks in oil vapors with the refrigerant and over operation it will lower the oil in the compressor. result is most likely a compressor seizing. the fact you said you had rubber burning means the clutch wants to turn the compress but cannot and the belt burns on the pully assembly. email me if you need or want more info. hope this helps.

 

I'm not a good source on this problem, but did not want to "not" respond.

Only help I can be is to suggest you do not run the AC until you know if the compressor is causing a "high load" rather than a simple clutch failure. If the compressor is bad, then the less "stuff" it pukes into the system the better.

If you do a search on-line you will find sources of tools for clutch removal, but I would try parts stores for loaners first.

Also would ask if you have the tell-tale spray of oil on the hood right above the compressor from the seal?

Sorry I could not be of more help with this.

Good luck, hope it's simple.

Pete

 

Thanks for the replies so far, I forgot to mention that this is on our 1993 Corvette.

Pete, I'd say that's an affirmative on the oil spray, there is a line of it about 1" long and another about 2" long BEHIND (closer to the driver when the hood is down) where the belt sprayed rubber up on the hood. And that's for replying Pete, you know I always look for you and David when it comes to ANY tech issues. You guys ROCK!!!!


[Modified by thrills, 7:51 PM 6/8/2002]

 

Ok he wants me to ask if there is any way to check if it's the clutch or if it's the compressor that's seized up without disassembling the system?

Also if we have to replace the compressor, dryer and accumulator do you feel the system needs to be vaccumed or can we just charge it ourselves. Keep in mind the AC worked FINE the last time we used it less than 30 minutes before.

 

To check the compressor clutch electrically you can just turn on the key and put the a/c to coolest position and have some one watch the clutch pull in. without the motor running it won't turn the compressor but it should engage. If it engages but when you run the motor it won't turn (burn belt) then the compressor is seized.

On replacement anytime the system is open to atmosphere it MUST be evacuated IF you want it to do its job properly and not damage the new components in the system. If it has been operating low on refrig and now oil, there is probably oil built up in the evaporator and that needs to be blown out of their by disconnecting the evap inlets and purging the system before you install the new parts. to do it correctly it must be triple evacuated before the final refrigerant charge is installed for operation. If you can find a club member with the tools you could do it but otherwise you may not get the performance you want from the a/c over the long term.

If you know what you are doing....its easy....but these systems are critical in the ref. charge and operation. The clutch would be simplier and the seal behind the clutch is not bad...mostly mechanical but you would still need a vaccum pump. Sorry its not the new you might like to hear.

Tom

 

First things first, if I was to reply to this as if I was talking to your husband, I could not say "babe", correct?
:lol: :lol: Ok, just kidding!

Now for the business.
Only two things could cause the compressor clutch to fail. One would be an over pressurization of the high pressure side of the a/c system. One example is a restriction in the system. The other could be a mechanical failure inside the compressor. This would be the more likely cause. In any event, clutch removal involves removing the compressor and disassembling it. So vacuuming and recharging the system is in order. This is a major task and needs an experienced tech to diagnose it to ensure that the system will be trouble free for years after the repair.

I know that you were expecting a simpler solution. But in this case, it is probably more complex than the average do-it-yourself repairer can handle.

:seeya

 

Thank you so much for your reply, i read it to him and he nodded and said ok. Thanks again :seeya We plan on keeping the car so we'll do it right.

 

HI Jenn> It looks like all the info you are getting is good. If the clutch is out or going bad on the A/C comp it will not engage as fast or at all. In a normal mode of operation the clutch will "click" or "snap" on as it engages and you can watch it sanp on and off as it operates during the operation of the A/C when it is on.,. Hope this all helps, Larry :cool:

 

Just a little more perhaps useless information. Many, many years ago my Dad lost a compressor in his Station Wagon (see, years ago). We found a replacement in the bone yard and I installed (we didn't have much funding at the time). I re-charged with R12 (cheap at the time). Worked for a minute or two like gangbusters, then went hot. Went back to bone yard and got another compressor, re-charged; same thing.

Asked my friend who used to be a technical trainer for GM to help, he brought his guages. He said we had a clog somewhere and needed to evacuate and take out the orfice valve. Did so, orfice valve plugged. He then said we can't fix this in your back yard. There was "stuff" in the system and a new orfice valve would plug again.

On my buddies advice brought it to a shop. They flushed with some sort of solvent, replaced the orfice valve and canister and it worked for years.

In your case the spraying of oil on the hood probably means the seal is gone, and you lost at least a good part of the oil charge. The compressor may have suffered from this loss of oil in the system. I'm glad some folks with AC experience have posted. AC is not voodo to me, just have very limited experience. Everything with it is so expensive you need to proceed carefully. At least you should already be 134a, so the charge is inexpensive.

I hope it works out well for yourself and Joel.

Pete

 

The same thing happened to me and It definitely sounds like the clutch. You wont know if the compressor is bad until you replace the clutch. As long as you didn't run the A/C for a long time, the compressor should be O.K.
Mine was.

 

Thanks for the reply, he's going to look at it today, Crossing my fingers that it's just the clutch :blueangel: And we did NOT run it long, I'd say about 2 mins, the cars with us radiod that we were smoking and we pulled right over and shut the car off immediatly.

 

Well, we tried the tip with putting the key at run with the AC on. He said the clutch did NOT engage. Just to be sure, we tried it on the '85 and he said it did and it was very obvious when it did.

Since the clutch did not engage, does that mean that the problem is the clutch?

 

Thrills, just because the clutch did not engage does not point it to the clutch although one would wish that to be so. On the accumulator (big silver canister) there is a pressure safety switch that is probably open and not letting the volts go to the clutch coil. pull the connector off the switch and use a small piece of wire to jumper the terminals on the connector. then turn on the key and a/c to full cool without the engine running and see what happens, if the clutch snaps in, the safety switch did its job and opened the circuit to stop continued use. if it doen't snap in, then we need to look at other checks. let me know what the result is. Your description of the event points to the compressor seizing but lets see the test results.

Another thing to do is to take the drive belt off, engage the clutch and rotate the compressor by hand. it should turn easy as there will not be any pressure differential. if you cannot rotate it then it confirms the bearings inside are seized.....new compressor is needed. hope this helps.