Air Condition Compressor noise

[BrinSCupstate]

My air conditioning compressor started making a noise that sounds like something rubbing the fan blade. I've checked the fan; and the AC has new belt and tensioner. It makes the noise when I turn on the AC and during acceleration. Can't hear it unless listening closely with the radio off. I called a local BMW mechanic. He said if it is cooling good, which it is, to keep running it until it quits. He said the AC compressors tend to make noice in these cars. Is this good advice or should I refrain from running or go ahead and replace? It's a 99 528I.

Thanks, Barry

[epeppino]

mine's been doing that for two years. I'll let you know when it stops working. cools perfectly.

[76papa]

I just replaced the compressor in my '99 528i because it made a loud noise which I suspect was a bearings problem and not a compressing problem because it cooled fine.
The new compressor is very quiet so I don't think it's normal for you to hear what your hearing.

[bimmerfiver]

What's the pressure in the A/C system? Only way to find out is to hook it up to gauge. Freon/refridgerant and oil (lubrication) travel together...gotta know if you are low on freon. I'd do this b4 my compressor kicked the bucket. It will give you a baseline and then you go from there.

I have my A/C system evacuated and re-filled every 2 years. My car is colder than Tantan's tit on planet Hoth. A low level can create noise.

Check other rollers/tensioners too!!! It could be one of them faking you out.

Also, the cheesy aluminum shields by the O2 sensors can make a rattle noise...

abc123:

http://74.125.113.132/search?q=cache...&ct=clnk&gl=us

[easymoney]

As long as it gets cold I would say don't worry about it! Just ensure that it's not the tensioner/pully that's making the noise.

[BrinSCupstate]

Bimmerfiver, The only guage I have is a cheap filling attachment I use on my truck. I put it on today and it showed 45 PSI with outside temperature at 77F. That is the blue area borderline to yellow area on the guage. According to the fill kit instructions, the charge is OK or maybe boarderline to overcharged. Should I let a little out? I've only had the car about a month so I hae not history on the car. It only started the noise this week.

[bimmerfiver]

I am not an A/C guru. It's actually a very simple system. I do know that too high or too low of pressure can create noise...

Read what Gorn has to say:

http://74.125.93.132/search?q=cache:...&ct=clnk&gl=us

Can you post a video of the noise? I mean...you need to be 100% certain this is your compressor as it could be a pulley/roller, the aux fan, water pump bearing etc. Can you look in the mirror and tell us with 100% assurance the noise is your compressor?

[BrinSCupstate]

I just replaced the waterpump, checked all pulleys and replaced the air compressor tensioner and pulley (unless the new one failed). It only does it when the AC is running and worst when turning on the AC. I can feel and hear a clunk when I turn the compressor by hand. I recorded the sound and just figured out how to post. It is loud when under the hood and having someone turn the AC on. Please review. I'm curious how common this might be.