[diablow16]

TLDR - I get an annoying whirl/whine when accelerating with the A/C on. I am leaning toward it being A/C clutch or bearing. Anyone successfully source the parts and repair their compressor?

I have confirmed the whirl/whine only happens with the A/C on and gets louder with rpm. This should rule out blower fan and points to something along the drive belt. I have read some people say it could be the belt slipping or a bad tensioner pulley or deflection pulley. The reasoning behind those is because when the A/C kicks on, it puts extra stress on the belt so it could be the belt/pulleys. I was able to take a picture of the compressor and have learned it is a DENSO 7SEU17C compressor. I believe the pulley size and type depends on the auto manufacturer. A bmw replacement is crazy expensive so I am hoping it is these common wear points and not the internal unit itself.

Anyone have experience or recommendations further? I am planning on buying a cheap auto stethescope and narrowing down the noise. It is clearly heard at 3500 rpm. Also, it isn't turbo noise/whistle. It is clearly a higher pitch sound than standard engine noise(with A/C off)

Thanks

[Scout10]

Verify the belt is in decent condition to spin an appliance. (cracks, shinny, etc)
Verify belt tension is within spec.

cheap test.....buy a spray can of belt dressing, spray & drive then listen
(also a 50 / 50 of dish soap & water in spray...... let dry a little, drive & listen
or dry bar soap same same, use caution ! tough to put on a moving belt !

I don't know if accessible on yours, i use to use a VERY long screwdriver
metal tip to the appliance and the handle to my ear.

How many miles on the vehicle, and what state has it mostly been used in.

[Tjalle]

If compressor - unlikely - you are done. Compressor should be available at non-BMW shop. Expensive.

More likely bearing in pulley - should also be available at non-BMW shop.

I would go to independent AC-shop.

[diablow16]

Thank you both for the responses. Car is a 2013 xdrive35i with 38k miles.

I popped the hood last night and noticed my tensioner pulley is noticeably moving and very noticeable when i turn on the AC. I don't know for sure but I would assume that the tensioner pulley should not move much. I have watched a few videos online of replacement on another N55. My sound is completely different compared to the videos but I am thinking that still might be my issue. My next step is to get a friend to bring it up to 3500rpm while I listen under the hood. I am hoping it is the tensioner pulley as that is a much easier and cheaper job.

[Tjalle]

Pulley should not move. Loose or more probably bearing is gone. Fairly easy to exchange. Make sure belt is "normally" tensioned after replacement.

[Scout10]

IF the tensioner pulley bearing is shot its gonna make noise alot more than just at 3,500. if the tensioner spring is shot, that will not
hold pressure on belt (depending on how bad the spring is) at higher rpm it will start to float with less tension, and the belt will sound off.
Acts the same way as worn brushes and spring on a commutator.

Is the A/C working okay ?

[diablow16]

The AC works fine.

So I replaced the tensioner pulley and drive belt this weekend. The sound still exists. My old tensioner pulley moved significantly under idle with the AC on so I was confident that was an issue. The new pulley moves, but not as much. So it might have been an eventual problem but it wasn't the noise I was going after.

I will have to spend more time diagnosing the issue before moving forward. I did spin the other pulleys with the belt off but no obvious sounds. Thinking it is a bearing for the AC compressor. I found an ebay seller in Germany selling a new pulley and AC clutch for $115 shipped.

For search reasons, if anyone is planning on doing a tensioner pulley replacement on an N55...buy a short T60 bit and you might be able to do the whole replacement without removing the radiator fan. I had to remove a huge amount of screws and a few annoyances getting the radiator fan out. My T60 torx bit is about 2.4" long. If I had one around 2" I could have probably gotten the job done much faster.

[hardparker]

Interesting to read this. I've got the same problem. I've taken it to the dealer once, recently. The tech claimed not to have heard the sound, but it's very obviously compressor noise, just like you're describing.

I'll have to re-schedule and see what they come up with next time. Sounds like you're on the right track. I'll let you know my solution if it gets resolved.

[Scout10]

Originally Posted by hardparker

Interesting to read this. I've got the same problem. I've taken it to the dealer once, recently. The tech claimed not to have heard the sound, but it's very obviously compressor noise, just like you're describing.

I'll have to re-schedule and see what they come up with next time. Sounds like you're on the right track. I'll let you know my solution if it gets resolved.

BUT . . . . it wasn't a compressor problem with OP ! It was a belt tension
issue. He replaces a pulley, belt and bingo no noise
and the A/C works!
and the sun rose in the East, and life moved on.

Is yours belt or compressor noise?

[hardparker]

Originally Posted by Scout10

BUT . . . . it wasn't a compressor problem with OP ! It was a belt tension
issue. He replaces a pulley, belt and bingo no noise
and the A/C works!
and the sun rose in the East, and life moved on.

Is yours belt or compressor noise?

It sounds like diablow6 is still having the compressor noise issue. The parts he replaced didn't solve the problem. His A/C always worked, but is noisy. Reread his last post.

But yes, I have the same A/C noise on accel. Dropping it off at the dealer on Monday for the second time for the same problem.

[diablow16]

To clarify, my annoying noise still exists. Tensioner pulley didn't fix problem. Curious to hear what hardparker's dealer says as I haven't had a chance to troubleshoot this further.

[diablow16]

Originally Posted by hardparker

It sounds like diablow6 is still having the compressor noise issue. The parts he replaced didn't solve the problem. His A/C always worked, but is noisy. Reread his last post.

But yes, I have the same A/C noise on accel. Dropping it off at the dealer on Monday for the second time for the same problem.

Any luck with the dealer?

[hardparker]

Originally Posted by diablow16

Any luck with the dealer?

They found the high pressure hose leaking at the crimp in the hose near the compressor fitting. They replaced it and... the noise is still there. I'll be re-scheduling for another appointment soon.

I believe you're correct in that it's the clutch or clutch bearing. That or the compressor itself. With less than 2,000 miles left on warranty, hopefully they'll get it squared away sooner rather than later.

[jeph72]

I had the same problem recently. It was driving me crazy so I took it in. They said my AC compressor needed to be replaced (2013 45,000 km). It was an extremely tough pill to swallow as my car is 6 months out of warranty, but I did it.

The sound is still there.

I took it back a week later and had a drive around with the shop foreman. He went and found another 2013 35i and took it for a spin and said he heard the same noise, so they've decided that it's a "normal" sound.

I explained to them that had I heard this sound last summer when it was under warranty I would most definitely had been in there every day until they figured it out. Surely the fact that I was willing to PAY for the problem to be fixed must account for something? They still said there was nothing they could do.

[rob116]

Originally Posted by diablow16

To clarify, my annoying noise still exists. Tensioner pulley didn't fix problem. Curious to hear what hardparker's dealer says as I haven't had a chance to troubleshoot this further.

I encountered the same high pitch whinning sound when accl. Off the ac then sound is gone. Belt are new. I also noticed the sound are gone or not noticeable if lower ac temp <20c. Chk in cabin blower and seems fine. Tensional seems ok n not much vibration. It was all quite when ac off. Mileage 62k. The car chg top gasket at 55k due to oil leaking but was degreased and rinse b4. Of course the oil leaks does sip into alternator and aircond compressor since it just right underneath. Any clue?

[rob116]

Originally Posted by rob116

I encountered the same high pitch whinning sound when accl. Off the ac then sound is gone. Belt are new. I also noticed the sound are gone or not noticeable if lower ac temp <20c. Chk in cabin blower and seems fine. Tensional seems ok n not much vibration. It was all quite when ac off. Mileage 62k. The car chg top gasket at 55k due to oil leaking but was degreased and rinse b4. Of course the oil leaks does sip into alternator and aircond compressor since it just right underneath. Any clue?

Solved. My mechanic added about 80-100ml of aircond compressor oil. All quiet now. Of course he to vacuum the gas out first before adding the oil. The rise seems smoother , chg of gear also smoother and lower in rpm and switching gear.

[epiphone3]

I had this issue and got the system recharged and bled properly and it went away.

[rob116]

Originally Posted by epiphone3

I had this issue and got the system recharged and bled properly and it went away.

My mechanic do did a simple vacuum when he suck out the gas but my problem was compressor oil dying up and there is oil stain on surrounding the compressor. Seems tht either it dries up or the original unit compressor oil are below level when stock new.