9two8

Took my car in for a re-gas today, and acrid smoke started coming from the front of the compressor, before this I noticed the battery gauge was reading low, but thought that was just because it was idling, and 928 electrics being what they are. I know I can just cut the belt to get me going, but was wondering if the compressor is finished, and what else I should do ? The air-con has never been up to much, so do I just live without it ?
Any tips or advice much appreciated ?

Ken
80 928 S
5 Speed

UK

herman maire

I would try to keep it working.... I was also going to look into this soon, I was wondering if there is a more modern compressor that would work with the newer r134 gas or does the old compressor work with the new gas?

I have some questions to figure out myself.

9two8

.., not too sure, but I think the mounting lugs on a 928 compressor are unique to the car ? unless anyone knows of a compatible compressor ?

Ken
80 928 S
5 Speed

UK

jeff spahn

Griffiths makes a kit. Put it in last month. Very easy. http://www.griffiths.com/porsche/ac/928ac/index.html

SQLGuy

Was it being recharged with R12, or has it been converted to R134a?

9two8

R12

Ken
80 928 S
5 Speed

UK

WallyP

First, you need to find out what happened.

There are three possibilities:
-The pulley bearing may have died. If this is the case, the bearing for the pulley, the outer part that always turns with the belt, has seized, and the belt is now toast. The only short-term way to get going is to cut or remove the belt, and if it has smoked for more than a couple of seconds, cut it. The bearing can be replaced without losing any refrigerant. Add a new belt and complete the recharge, and you are good to go.
-The compressor may have seized. Possibly already bad, and when the tech added enough refrigerant to get the compressor clutch to kick in, the compressor seized. Replacing the compressor and receiver/dryer, and cleaning the rest of the system is the only way to get it going.
-The tech may have slugged the compressor. That is, the tech may have been adding liquid refrigerant to the system, and allowed the liquid to get into the running compressor. Liquid is virtually incompressible, so the compressor would instantly stop. The clutch would smoke and stink. If you are very lucky, there might not be major damage, and the only thing that is needed is to have a competent tech complete the recharge.

If you can get to the compressor, try turning the center part of the clutch assembly. If it will turn by hand, try running the A/C again. If the compressor turns with no smoke and noise, you may be in good shape.

9two8

Thank,s for the input Wally, my car is having an autopsy tomorrow ?? so will find out what the damage is ?

Ken
80 928 S
5 Speed

UK

9two8

..., an update, it seem,s the clutch has failed, after vaccuming the system we only got about 15 grms in the system, and the clutch would not engage, I put a wire from the compressor feed wire to the hot post, and nothing, ie no clutch engaging, only a slight spark from the com wire ?
I guess it,s a case of trying to locate a clutch now.

Ken
80 928 S
5 Speed

UK

Bill Ball

In one 928 I did some AC work on I burned out 2 Denso compressor clutches before I determined that the compressor was partially seized.

https://rennlist.com/forums/928-foru...ure-blues.html

You can buy the clutch (although not cheap), but I would just replace the entire compressor/clutch unit. I learned the clutches rarely burn up on their own.

vze2jshn

Try to determine why the clutch failed. Did the bearings in the clutch burn up? If so, replace the bearings if the rest of the clutch is OK or replace the clutch if necessary, possibly with a used one that you might put new bearings in.

9two8

Thank,s for that tip Bill, yes that has gone through my mind, and noted.

Greg, that is a possibility, as for a couple of years now, there is sometimes a very shrill metallic sound emanating from the compressor area. i posted on here a while back, to see if anyone knew what it could be but no remedy ? compressor clutch bearing maybe on it, s way out ??? and decided to die on Tuesday !


Ken
80 928 S
5 Speed

UK

vze2jshn

On my '78 there are two bearings in the clutch which you can get the ID numbers off of and source through a bearing distributor. My '78 also has a rubber component that can break and cause slippage that will result in an acrid smoke situation in which case you'll need another clutch new or used. When you take the compressor off see if it turns freely, if so you may be lucky and only need a clutch or clutch repair.

Bill Ball

My contention, learned the hard and expensive way, is that the clutch rarely burns out on its own. While it may suffer a wire break failure, burning up/melting the way the ones did in the thread I linked means something else is going on.

9two8

The belt is still on the compressor, have,nt had time to take it and the clutch off, but hopeing to in the next few days, the pulley wheel is still turning with no problem IE no nasty noises, and the belt is in good condition, after all the smoke !
Once we get it off and examined, hopefully things will be more clearer, particularly the bearings ?
Thank,s for your interest

Ken
80 928 S
5 Speed

UK