So a couple of weeks after an indy installs a new R4 compressor, expansion valve and drier, my wife tells me that the A/C is out. I connect the manifold valves on the previous owner's R34 converted system and low and high side both shows 95 psi so I'm thinking slow leak as it should be 125 psi?? I turn on the car with AC on and no change so I'm thinking no compressor and I see the new belt shredded torn. However the new compressor rotates freely so not seized. So what make a new belt shred when the compressor doesn't seize? I think the indy put the seal rings in the incorrectly in the R4 so it leaks. So I have to mess with the seals, change the belt, vacuum and recharge the system, arrggghhh! I pay the indy so I don't have to mess with now I have to! How did the new belt shred?

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Is it seized with the clutch engaged or did you spin it freely (without engaging clutch)

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TC
Current stable:
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Spins freely without engaging clutch, I think. It just spins by hand with the engine off. I didn't try it with the engine on.

the compressor is the interior ring on very very front, the outer part where is the belt contacts is just the clutch pulley. System-off charge pressure will vary with ambient temperature, so 95 is not necessarily out of line.

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It is 85 ambient outside now. It was the clutch pulley that I was spinning. Why would the new belt shred, too tight or too loose?

Which tells you nothing about the condition of the compressor. Some parts stores have compressor wrenches in their loaner tool line-up. You might want to round one up and see if the compressor itself rotates.

Pulley misalignment would be high on the list of suspects. Did the spacers on the compressor go back in the correct locations?

Don't know, indy did the job.

If the clutch spins, but the compressor is seized, then once the clutch engages (engine running), it won't be able to spin the compressor, hence destroying the belt........(if I read this correctly?)

OP, what's the verdict?

The compressor is not seized, it turns by hand. Dealer has ordered me an A/C beft which I will painstakingly replace (heard it was a royal PITA) and see how it goes. If it works I hope it gets me through August. Apparently July was the hottest July in many a year, hotter than the dust bowl years in the 30's.

That sounds a lot like "doing the same thing and expecting a different result."

It does, but I didn't do the job before. I'll install it and look for misalignment. Maybe it jumped the pulley because it was too loose?

very common occurrence when too much oil is in the system. look over the bill for installing the compressor. EXACTLY what is itemized?
oil will slug, and lock up the pistons in the compressor, spinning the belt... POOF!

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I had a compressor that would run for an hour or so then seize. Maybe thats happening here.

But the compressor turns by hand so shouldn't it be ok? They didn't itemize anything.

nope.
it'll slug oil or refrigerant after it's running for a while.
only thing to do is pull the compressor, flush each and every line and component, then replace dryer, and put in the correct volume of oil back where it is supposed to be, evacuate the system, then weigh in the correct charge of R12.
if you are using R134, weigh in 60% of the R12 weight, and adjust charge to get best cooling... but do not exceed 80% of the R12 charge.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!