More help needed - burning plastic smell & smoke
03-04-2007, 07:24 PM
#1
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More help needed - burning plastic smell & smoke
Ok I finaly had the car out this afternoon after about a month in the garage and what i thought was a DME problem yesterday. I was running at a pretty good pace on the highway 6000RPM with the a/c on all seemed fine until i get a strong smell of plastic burning. I pull over to have a look and black smoke pours out from the engine scared the crap out of me. Lift up the lid and noticed burnt plastic splattered on right side of engine bay. I thought it was the drive belts which i just replaced last fall but it was not. The attached photo shows where the plastic was melted (circled). Its was extremely hot to the touch, i actually poured a bit of water on the circled part in the photo and it steamed. I guess this is the a/c compressor. In the photo, the circled part, i am able to hand turn it seems loose and held on with some rivets. Anyone else experience this problem? -Joe 96 C4 Cab
03-04-2007, 08:28 PM
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Hi Joe,
The part you have circled is the AC compressor clutch. When the AC is off, or when the compressor cycles, the clutch can spin freely. It does sound like the AC compressor has frozen. It should be okay to drive the car as long as you don't turn on the AC.
If the AC compressor grenaded it can send bits of metal debris throughout the AC system, so repairs need to take that into account...
The part you have circled is the AC compressor clutch. When the AC is off, or when the compressor cycles, the clutch can spin freely. It does sound like the AC compressor has frozen. It should be okay to drive the car as long as you don't turn on the AC.
If the AC compressor grenaded it can send bits of metal debris throughout the AC system, so repairs need to take that into account...
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03-04-2007, 09:22 PM
#8
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1) Yes the spatter on the motor mount is from the melted plastic/rubber
2) I agree with what you are saying about the a/c clutch. I did have the a/c running at the time. With the A/c off the part circled does not turn (however i can turn it by hand and it seems a bit loose and rubbing on something) Seems to be held with studs to the a/c compressor. The belt on the a/c is in good shape as well, far as i can tell.|
3) I just cant figure out what actually melted.
Looks like an expensive fix to me.
2) I agree with what you are saying about the a/c clutch. I did have the a/c running at the time. With the A/c off the part circled does not turn (however i can turn it by hand and it seems a bit loose and rubbing on something) Seems to be held with studs to the a/c compressor. The belt on the a/c is in good shape as well, far as i can tell.|
3) I just cant figure out what actually melted.
Looks like an expensive fix to me.
03-05-2007, 12:46 AM
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It is probably the AC compressor clutch facing, the AC drive belt, or both that melted. If the compressor froze up, and the belt is still trying to spin the compressor, something has to give.
03-05-2007, 01:35 AM
#10
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start the car and have a look at what the compressor is doing, or not doing for that matter. Look and smell.
03-05-2007, 01:39 AM
#11
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and get to the bottom of why your CCU rear blower temperature sensor wiring was causing engine running problems. If the two problems are connected this won't be the last thing that melts, burns and possibly catches on fire.
03-05-2007, 02:54 AM
#12
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Originally Posted by c4-toy
1) (however i can turn it by hand and it seems a bit loose and rubbing on something) Seems to be held with studs to the a/c compressor.
but by the 10 mm nut in the middle.
You can remove the clutch with the compressor in the car for inspection.
To remove, tape the metal black small wheel on all the circumference, not to scratch it.
Use a regular oil filter clamp to hold it enough not to turn.
Use a 10mm snap on and unscrew, pay attention not to drop the nut and washer.
release the oil filter grip.
pull gently the clutch outside and inspect.
ON SECOND THOUGHTS, is the 10mm nut THERE?
I rechecked the images and it seems its not there?????
03-05-2007, 05:09 AM
#13
Looking at the "splatter line" I would also look closley at the plastic belt roller on the left side. They tend to make a lot of noise then lock up on failure. I could see how this black plastic part could melt down fast.
Cheap easy fix if im right.
Cheap easy fix if im right.
03-05-2007, 11:11 PM
#14
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Originally Posted by geolab
The A/C clutch you are talking about is held to the compressor not by the studs,
but by the 10 mm nut in the middle.
You can remove the clutch with the compressor in the car for inspection.
To remove, tape the metal black small wheel on all the circumference, not to scratch it.
Use a regular oil filter clamp to hold it enough not to turn.
Use a 10mm snap on and unscrew, pay attention not to drop the nut and washer.
release the oil filter grip.
pull gently the clutch outside and inspect.
ON SECOND THOUGHTS, is the 10mm nut THERE?
I rechecked the images and it seems its not there?????
but by the 10 mm nut in the middle.
You can remove the clutch with the compressor in the car for inspection.
To remove, tape the metal black small wheel on all the circumference, not to scratch it.
Use a regular oil filter clamp to hold it enough not to turn.
Use a 10mm snap on and unscrew, pay attention not to drop the nut and washer.
release the oil filter grip.
pull gently the clutch outside and inspect.
ON SECOND THOUGHTS, is the 10mm nut THERE?
I rechecked the images and it seems its not there?????
geolab, yes the 10mm nut is there. Today i was able to easily remove the clutch by just loosening the 10mm nut without even needing to clamp anything it just came right off. After inspecting looks like burnt carbon all over the 2 clutch parts (see photo). The part on the left seems to be made of some soft material. So far am starting to see convincing evidence that the compressor froze (if there is such a thing). Bottom line looks like i need a new compressor i think. This looks like more of a job than i can handle. Any idea cost to repair? Thx Joe
03-05-2007, 11:43 PM
#15
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The good news is that rebuilt units are available. The bad news is it still won't be a cheap fix.
I went through this problem with my '85 Carrera and had to deal with the R12 issue as well.
I went through this problem with my '85 Carrera and had to deal with the R12 issue as well.