[canadae90]

Hey all,

I had a noise coming out of my engine bay, it sounded like a whine that you might hear from a car with low power steering fluid or a bad alternator. It sounded like one of those toy cars that kids drive in. I was able to diagnose and fix the problem. Here is a video I made explaining the process and what you need to fix it. It wasn't the belt, idler pulley or belt tension pulley. It was the AC compressor. If you have any questions feel free to comment here or on the video. Happy to help the community! This noise was driving me NUTS!

[desertman123]

Oo I've heard this in my car a bunch too, wonder if it's the same issue

[canadae90]

Originally Posted by desertman123

Oo I've heard this in my car a bunch too, wonder if it's the same issue

The key is to figure out where the sound is coming from...the first step I'd suggest is taking your serpentine belt off and turning on the engine to ensure the sound is coming from one of the pulleys. After that you can spin the pulleys with your hand listen for any weird noises. Try and figure out with your ear exactly where the sound is coming from. In my case I noticed the noise was coming from behind the passenger side head light, exactly where the AC compressor is. Let me know if you need anymore info!

[tlow98]

Good post! These motors certainly are ‘whiney’

Have you had a chance to replace the bearing and verify your thoughts?

[canadae90]

Originally Posted by tlow98

Good post! These motors certainly are ‘whiney’

Have you had a chance to replace the bearing and verify your thoughts?

I've just ordered the bearing. It's not that easy to get since it's not an industrial bearing but an automotive one. I will update this post when it comes in.

I have good reason to believe it's the pulley bearing because I used to have an 03 Benz C240 and its AC compressor stopped working as well. I happened to save it (the old compressor) and I found out that it's basically the same AC compressor that's in the E90! The best part was that the bearing in that one was shot too, so I'm guessing that it has to do with that specific AC compressor (Denso model) losing its bearing after about 200 thousand KM. That's the reason I know that the bearing size is 35x52x12. The AC in the E90 works perfectly fine and the noise doesn't change when you turn on the AC so I know for a fact that it's the pulley.

I'll update this post with photos of the pulley being removed and the old bearings being removed and replaced. I'm almost certain that the bearing is exactly what's causing the issue.

[labrador]

Not sure about the MB but E90 uses variable displacement compressor, so there is a bearing in the pulley?

also is there enough freon in the system?

[tlow98]

Originally Posted by canadae90

I've just ordered the bearing. It's not that easy to get since it's not an industrial bearing but an automotive one. I will update this post when it comes in.

I have good reason to believe it's the pulley bearing because I used to have an 03 Benz C240 and its AC compressor stopped working as well. I happened to save it (the old compressor) and I found out that it's basically the same AC compressor that's in the E90! The best part was that the bearing in that one was shot too, so I'm guessing that it has to do with that specific AC compressor (Denso model) losing its bearing after about 200 thousand KM. That's the reason I know that the bearing size is 35x52x12. The AC in the E90 works perfectly fine and the noise doesn't change when you turn on the AC so I know for a fact that it's the pulley.

I'll update this post with photos of the pulley being removed and the old bearings being removed and replaced. I'm almost certain that the bearing is exactly what's causing the issue.

What a coincidence. Or, maybe not, given the manufacturers.

Either way, great contribution to the forums. Appreciate the posts.

[canadae90]

Originally Posted by labrador

Not sure about the MB but E90 uses variable displacement compressor, so there is a bearing in the pulley?

also is there enough freon in the system?

E90 Ac compressor:

https://www.ebay.com/itm/Denso-A-C-A...-/131517803930

MB c240 2003:

https://www.ebay.com/itm/NEW-Mercede...QAAOSwjL5ZKSDZ

Both made by Denso, basically the same part. There will be a bearing in the pulley, there usually always is in every pulley. Yes there is, the thing cools perfectly. I could be wrong however, but I'll try and update this post soon with the results of the pulley repair. I'm hoping my hunch is proven to be right, I was right about the AC compressor causing the whining noise.

[canadae90]

Originally Posted by tlow98

What a coincidence. Or, maybe not, given the manufacturers.

Either way, great contribution to the forums. Appreciate the posts.

No problem, happy to help out the community. As a key tip for any engine noise chasing: always remove the belt and start the car to determine if it's the engine causing the noise or one of the pulleys. Given the reliability of the straight-six, it's almost always one of the pulleys. Another hint is to really put your ear up to the engine and find where the noise was coming from. I was worried it would be the alternator but the noise wasn't coming from there.

I really wish I had filmed the noise it made before I made the change and included it in the video, but I can describe it as a whining noise. This video is a good representation of the noise my car made:

The poster of this video replaced the tensioner pulley and got the noise to go away. I did the same (my tensioner was also shot) but that didn't get rid of the noise. I should've followed my ear. Either way, changing the belt, the tensioner pulley and the idler pulley is always nice as preventative maintenance! These N52s will go a long time if you treat them with love.

[lab_rat]

Originally Posted by canadae90

I've just ordered the bearing. It's not that easy to get since it's not an industrial bearing but an automotive one. I will update this post when it comes in.

I have good reason to believe it's the pulley bearing because I used to have an 03 Benz C240 and its AC compressor stopped working as well. I happened to save it (the old compressor) and I found out that it's basically the same AC compressor that's in the E90! The best part was that the bearing in that one was shot too, so I'm guessing that it has to do with that specific AC compressor (Denso model) losing its bearing after about 200 thousand KM. That's the reason I know that the bearing size is 35x52x12. The AC in the E90 works perfectly fine and the noise doesn't change when you turn on the AC so I know for a fact that it's the pulley.

I'll update this post with photos of the pulley being removed and the old bearings being removed and replaced. I'm almost certain that the bearing is exactly what's causing the issue.

This is a great thread OP.

I've had this exact noise (whine that varies with rpm), even after replacing the tensioner pulley.

I will be watching the outcome of your repair...hopefully the compressor bearing and/or pulley is the simple fix.

I found a bearing matching the size you stated (on Amazon of course), but just to verify, could you post the part numbers for the compressor bearing and pulley & where you bought it so we could follow suit if this does work?

Thanks!

[canadae90]

Originally Posted by lab_rat

This is a great thread OP.

I've had this exact noise (whine that varies with rpm), even after replacing the tensioner pulley.

I will be watching the outcome of your repair...hopefully the compressor bearing and/or pulley is the simple fix.

I found a bearing matching the size you stated (on Amazon of course), but just to verify, could you post the part numbers for the compressor bearing and pulley & where you bought it so we could follow suit if this does work?

Thanks!

I dont believe that there is a part number for the bearing as it's not available to buy through any automotive repair shop. Most legitimate places will only sell the AC compressor itself.

https://order.germanparts.ca/product...pe=APPLICATION

This is the compressor my car (09 328xi) needs. OEM #: 64529122618

You would then google the pulley for this particular compressor unit. There is no part number for the pulley I believe since BMW considers the pulley and the compressor as one unit.

https://www.ebay.com/i/142684190352?chn=ps&dispItem=1

I believe that the link above is the pulley you want to buy. It comes with the hub plate which makes the replacement process a little simpler.

This video will show you how to replace the pulley:

I'm pretty certain that all of these links are correct. I should be able to get the bearing replaced this weekend or next weekend. Of course I will detail how it went and if the results are correct. If you don't have a crap ton of tools or a spare machine shop that you can use, I would recommend replacing the pulley instead of the bearing. Make sure you get a quality bearing too! Some of them come with a lifetime warranty, and who wants to do the same job twice.

Also you should make sure that the noise is in fact the AC compressor pulley for you, try to bypass it with a shorter belt or just put your ear up to the AC compressor area while someone revs the engine for you. If it is, I recommend you bypass the AC compressor ASAP! A faulty bearing will, eventually, cause the pulley to "wobble" and whittle down the shaft that the pulley is on, causing damage to it and making a pulley replacement impossible. I've also read horror stories of the pulley even coming off and the belt then coming off while driving. I definitely recommend you bypass it and get it sorted quickly. My noise was a lot worse than the video I linked above. Will update this post with the repair, all the best to you!

[atmosphericM]

Vid of whine? I think these cars just sound whiny. Mine has less than 30k on her and at first I noticed the engine just, well, whines. Although it was a smooth and high-pitched whine, unlike my Boxster's failing power steering whine. Now I don't even notice it (PE helps but still).

Good job on diagnosing your noise in particular, though. Thanks for contributing. Cheers.

[lab_rat]

Originally Posted by canadae90

I dont believe that there is a part number for the bearing as it's not available to buy through any automotive repair shop. Most legitimate places will only sell the AC compressor itself.

https://order.germanparts.ca/product...pe=APPLICATION

This is the compressor my car (09 328xi) needs. OEM #: 64529122618

You would then google the pulley for this particular compressor unit. There is no part number for the pulley I believe since BMW considers the pulley and the compressor as one unit.

https://www.ebay.com/i/142684190352?chn=ps&dispItem=1

I believe that the link above is the pulley you want to buy. It comes with the hub plate which makes the replacement process a little simpler.

This video will show you how to replace the pulley:

I'm pretty certain that all of these links are correct. I should be able to get the bearing replaced this weekend or next weekend. Of course I will detail how it went and if the results are correct. If you don't have a crap ton of tools or a spare machine shop that you can use, I would recommend replacing the pulley instead of the bearing. Make sure you get a quality bearing too! Some of them come with a lifetime warranty, and who wants to do the same job twice.

Also you should make sure that the noise is in fact the AC compressor pulley for you, try to bypass it with a shorter belt or just put your ear up to the AC compressor area while someone revs the engine for you. If it is, I recommend you bypass the AC compressor ASAP! A faulty bearing will, eventually, cause the pulley to "wobble" and whittle down the shaft that the pulley is on, causing damage to it and making a pulley replacement impossible. I've also read horror stories of the pulley even coming off and the belt then coming off while driving. I definitely recommend you bypass it and get it sorted quickly. My noise was a lot worse than the video I linked above. Will update this post with the repair, all the best to you!

Thanks for the detailed response. I'm looking forward to the outcome of the repair, and hope it cures the issue.

[labrador]

Maybe you would want to locate the whine. Or whistle from vacuum leak?

Originally Posted by atmosphericM

Vid of whine? I think these cars just sound whiny. Mine has less than 30k on her and at first I noticed the engine just, well, whines. Although it was a smooth and high-pitched whine, unlike my Boxster's failing power steering whine. Now I don't even notice it (PE helps but still).

Good job on diagnosing your noise in particular, though. Thanks for contributing. Cheers.

[canadae90]

UPDATE!!! This shit has been in the works for quite some time now lol.....so as described above, the bearing in my AC compressor pulley was the cause of the noise. I was able to remove the pulley from the AC compressor and swap the old worn out with a new one. Video and pictures below. If you hear that whining noise, check out your AC compressor pulley! First check if the noise persists with no belt on and then see if the noise persists when you bypass the AC compressor. Happy to help with any other questions. This was a pain in the ass to do! I messed up the old pulley cover but thankfully I had some spare parts laying around from an old 2003 Benz C240 AC compressor, they use the same one.

View post on imgur.com

[canadae90]

bump for visibility

[drtmvr]

Did you change out the bearing with the compreessor still in the car?

Thanks

[Ilianagon14]

Does anybody know where I can purchase the headlight bulb retainer clip?

[Navko]

I own an e92 with the n55 and have cared for it well. no mods, racing, or anything of the like. Only use non-ethanol fuel. It runs and shifts like new.

Lately I have been fixated on this weird jet-engine/ supercharger-like whine/whir/ hum most noticeable in the cabin. I have gone through a great many bimmer (and non) blogs/postings to find a replica of this sound or at least something close to it, but to no avail; a first since 2011.

BMW SA heard video and said it was a first for him as well. He thinks it may be coming from the speakers or something. He said the audio amp sometimes make sounds. I think he may be wrong.


I was wondering if your talented ears can tell me where it may be coming from? Your commenters are also welcome to share their opinion.

The video is on my YouTube. It is my first ever upload to YouTube and Bimmerpost. Please forgive me if I may have intruded.

Tks.

[juld0zer]

Manual or auto?
That sounds more like a diff noise.. My current car does it only on coast or 70km/h +/- 10%.
Some will make the noise on acceleration.

My old N55 135i had the diff whine at 70km/h also but there was a faint whine from the engine bay in the lower gears whilst accelerating, mainly with the AC on though.

Your AC is off but your video doesn't show your tacho or speedo which may help jog people's minds

[Navko]

Originally Posted by juld0zer

Manual or auto?
That sounds more like a diff noise.. My current car does it only on coast or 70km/h +/- 10%.
Some will make the noise on acceleration.

My old N55 135i had the diff whine at 70km/h also but there was a faint whine from the engine bay in the lower gears whilst accelerating, mainly with the AC on though.

Your AC is off but your video doesn't show your tacho or speedo which may help jog people's minds

Thank you for your reply. My vehicle is an auto. And the whine is tied to the acceleration. It starts off real faint at 1k and is drowned out by 4K rpm. No noise in park or neutral.

[abrahamlincoln]

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