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1997 E320
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Discussion Starter · #1 ·
After getting off of work today I got into the car and turned it on. Everything was normal until I turned my A/C on, as soon as I did I heard a scraping sound as if a wire hanger was being spun around in my engine and the car shut off. Upon turning the AC off I got home without a problem and again tried the AC where it was safe, it turned off again but this time I was in drive. What could this be?
 

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1994 E320 Wagon,1999 E320 Wagon,2000 E 320 Wagon, MGB Track/Rally, ,1988 300E ,more....
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Check

that the ac compressor is not froze up.Stand back keep everything(fingers etc.)clear and have someone duplicate what you have been doing.If you cant duplicate it or see it in short order get it to a shop before you possibly do some real damage.
ohlord:bowdown:
 

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Discussion Starter · #3 ·
the ac compressor is NOT froze up? what does that mean? Are you telling me to open the hood and watch the engine while someone else duplicates my actions from when i got off? Thanks so much.
 

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the ac compressor is NOT froze up? what does that mean? Are you telling me to open the hood and watch the engine while someone else duplicates my actions from when i got off? Thanks so much.
Hey, twig. I agree that ohlord is on the right track here. "Froze" is probably the wrong modifier in the air-conditioning context, though.;) The compressor has a big bearing that the pulley just spins on so it's pretty much a freewheel, very little drag. However, when you engage the AC the clutch engages the compressor shaft, which is supposed to start the compressor spinning. If the compressor has seized however (think of an engine that seizes, it can't be turned, right?), it's just like something very strong "grabbing" the fan belt, and that could account for the awful noise and the lug on the engine that caused it to stall.

I'd be a bit leery of standing near the open engine bay and having someone engage the AC; given the placement of the compressor you'd have to be standing right in line so that if the belt were to fail, you could be injured. If you don't mind sacrificing a belt, just leave it in park, rev it up to about 2,000 - 2,500 RPM and then engage the compressor. If it's seized you'll get a shriek/howl and possibly some burning rubber-ish smells from the belt, and it may snap in the process. (You could also put some tape on the front of the compressor (not on the pulley as it always turns) and then see if it has moved after the test.)

As an alternative test you could let things cool down and remove the fan belt and then apply 12V to the clutch connections (follow the wires, near the front of the compressor, you'll hear it click in). Then -- be sure to wear gloves -- try to turn it by hand. It should be very stiff, but if you have average arm/upper body strength and it isn't seized up, you'll be able to move it. If not, further confirmation.

Take care and enjoy the ride,
Greg
 

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A seized compressor

in the automotive lingo is referred to as froze up,not as in freezing as in the bearing is shot.
So that is what I was suggesting that you check:)
ohlord:bowdown:
 

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'98 E430
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I would assume that the compressor is froze up and not do any more testing lest you lose the belt and end up walking. Think about it. A/C on-noise. A/C off-no noise. Car dies both times. Age of your car and location makes it fairly probably that it is the compressor.
 

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in the automotive lingo is referred to as froze up,not as in freezing as in the bearing is shot.
So that is what I was suggesting that you check:)
ohlord:bowdown:
Not to quibble, since we both know what you meant, but for others reading the thread and trying to diagnose an issue, the bearing in Twig's car is technically fine, since it spins freely until the clutch is engaged. Rather, it sounds as though the internals of the compressor are what have done froze up. :)

Typically, when the big AC clutch/pulley bearing starts to go you get treated to a whiny grating sound anytime the engine is running; curiously in the early stages engaging the compressor will sometimes quiet the bearing noise. Eventually it won't, the noise increases, and then the bearing either seizes or comes apart...either of which will leave you stranded. On the other hand, so long as the bearing is good you can ignore a seized compressor as long as you don't mind being without (a) air conditioning or (2) a defroster.

Take care and enjoy the ride,
Greg
 

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1998 C200 Classic; 1992 230E Sportline; 1994 C180 Classic (Sold)
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A follow up to this issue.

I have a 1998 C200 manual. I know my car has a seized A/C compressor.

Every time I push the clutch in I hear a grating sound. I assumed it was due to the compressor but why do I only hear it when the clutch is in? Could it be due to something else?

Oh, and I always leave the A/C switched off until I get the compressor replaced next month.

Thanks,
Jase
 

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2001 SLK 320(217K Miles), 2002 E320 Special Edition(183K Miles)
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Thrust bearing is going - probably all the Durbs humidity causing rust. It's a cheap part, but I think you have to pull the gearbox to replace it. Hopefully it is just starting to go and has not yet damaged anything else. You may as well replace the clutch plate at the same time while you have the gearbox out.
 
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