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Need compressor information

2Thirty on Mon May 12, 2008 2:56 AM User is offline

Year: 1993
Make: BMW
Model: 325i convertible
Engine Size: 2.5L
Refrigerant Type: R-134a
Country of Origin: United States

Some time ago, I was repairing the AC on my 94 Astro van. With the help of the folks here, I was able to get it working perfect and learn a lot about auto AC.
I am returning to the well to see if any one can help me determine what compressor to get to replace a bad one on a 1993 BMW 325i convertible I bought last week.
It's a beautiful car, but the owner said the AC had gone out some time ago, and the mechanic suggested "closing off" the AC if it wasn't going to be repaired.

The "closing off" was putting a new belt on that bypassed the compressor pulley.

I have been replacing a few things on it the last few days, mostly bulbs. I'm finding that the parts stores list the wrong parts for this model/year.
I was going to start the AC repairs by buying a re-manufactured compressor, but with the parts I have bought so far being about 50% right, and that's all of the local and on line parts stores, I'm a little gun shy about buying a compressor just because it's the listed replacement.

So, my question is, does any one know what compressor fits in this little fellow?

It is a:

325i convertible
build date is 12/92

markings on compressor are:
6452 8 391 152

Two pictures of the compressor:

Thanks for any help,

mk378 on Mon May 12, 2008 10:31 AM User is offline

How are you sure that the compressor is bad? Is it set up for R-12 or R-134a now? Is there any pressure in the lines?

bearing01 on Mon May 12, 2008 10:36 AM User is offline

There may be some useful info on the website. I didn't read the following article but from the pictures of them with the low-side refill can I would take their instructions with a grain of salt.

This is a good website to determine dealer part numbers and exploded pictures:

I would recommend you purchase the Bentley manual for this car at because it will save you much money in the long run if you turn your own wrenches.

I also wouldn't recommend a rebuilt compressor, just from personal preference. I would replace it with a new OEM-brand one from ACkits.

bearing01 on Mon May 12, 2008 10:41 AM User is offline

I'm pretty sure BMW started using R134a in the 1991 models, so this one should use that also. I'm also going to guess that's a NipponDenso compressor. It should have seals & gaskets that are R134a compatible even if the system was for R12.

Edited: Mon May 12, 2008 at 10:42 AM by bearing01

2Thirty on Mon May 12, 2008 12:48 PM User is offline

The previous owner said they took it to a shop when the AC stopped working. The shop said it was a bad compressor.
The owner was in the process of buying a new car, and the shop said they could just bypass the compressor. That's what they did.

I haven't checked for pressure yet. I will check this evening.
While changing the oil yesterday, I gave the pulley a few turns, and could hear a scraping noise.
The shop the previous owner used for the car is reputable, and has kept the vehicle in top condition. Not that they couldn't be wrong, but my guess is they were being honest with the owner.

Your suggestion about the manual and the new compressor seem to make sense. Buying it from the guys at ACKits would be perfect, as the help from this forum and items I have bought from them in the past have been perfect.


mk378 on Mon May 12, 2008 1:06 PM User is offline

If it's just that the pulley scrapes, but the compressor internals are OK, you may be able to buy a bearing or clutch set for the compressor instead of replacing the whole thing. This would involve an even more complicated search for the right part though.

bohica2xo on Mon May 12, 2008 2:23 PM User is offline

Parts for that car will always be confusing, there was a lot of transition in those years.

That compressor is a seiko-seiki unit, with a vee belt drive Like This. Some books show a different compressor with a serpentine drive...

If the clutch bearing was dying, the mechanic did the right thing removing the belt. It may be repairable, the bearing is easy enough to get. If the noise came from turning the pulley on the bearing and not the compressor itself, the noise is likely the bearing.

If you still have pressure in the system, and the compressor internals turn smoothly, you can probably fix it rather than replacing it.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

2Thirty on Mon May 12, 2008 3:24 PM User is offline

Thanks, I will hook her up this evening and see.


2Thirty on Mon May 12, 2008 7:09 PM User is offline

Hooked the gauges up and to my surprise the high and low side both read 94 pounds.
(I wasn't surprised they were the same, but that they had any thing in them to read at all)

I will probably pull the compressor off this weekend. Do you know where I can buy the bearings for this compressor?


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