Metallic/Squeaking Noise under deceleration (external)

[F1FL]

Hi all,

Yesterday morning as I was driving to work I noticed a decently loud metallic/squeaking noise coming from outside of the car under deceleration. Basically when I let off the gas I could hear it going down from 4th - 3rd - 2nd gear. It is audible in the cabin but especially so with the windows down, decelerating next to other cars/curbs where the sound would reverberate back.

It happens when the brakes are not being applied. Its a very strange sound I've never heard before on any car. I cannot hear it upon acceleration. Please let me know what you all think, its driving me nuts and I'll be taking it in for service if I can't diagnose it!

Edit:

[monterey]

I just changed my idler/deflection pulley for a squeaky noise. Might be that too?

[F1FL]

Originally Posted by monterey

I just changed my idler/deflection pulley for a squeaky noise. Might be that too?

I looked up a post on here about the idler pulley and it sounded different, but I guess it could possibly be

[cclinard1]

I had a wheel bearing go bad that made a similar noise. Do you still hear it if you move the steering wheel from side to side while moving?

[F1FL]

Originally Posted by cclinard1

I had a wheel bearing go bad that made a similar noise. Do you still hear it if you move the steering wheel from side to side while moving?

I can give this a try later today after work. One thing to note is this just began a day after I did a 180+ mile road trip. I did notice some noise/rumbling feeling at highway speed towards the end of the trip.

[cclinard1]

Originally Posted by F1FL

I can give this a try later today after work. One thing to note is this just began a day after I did a 180+ mile road trip. I did notice some noise/rumbling feeling at highway speed towards the end of the trip.

I had same symptoms. Try moving the wheel. If it is a wheel bearing, the noise will change with side to side movement because of the additional pressure placed on the wheel at that time.

[monterey]

Well the idler pulley would make the noise even when stationary

[F1FL]

I can try to record a video later today. Almost as though I'm dragging tin cans behind my car. It does however sound like its coming from the wheels, and I've read could be a pebble stuck in the rotor/heat shield.

[///WeissBisBlau]

Originally Posted by F1FL

I can try to record a video later today. Almost as though I'm dragging tin cans behind my car. It does however sound like its coming from the wheels, and I've read could be a pebble stuck in the rotor/heat shield.

Yep, that's exactly what it sounds like. Classic pebble-in-heatshield syndrome. It's happened to me a couple times, and it sounds just like that. Depending on the size of the pebble, it can sound horrific--like your wheels are getting ready to fall off! Failing that, however, it next sounds most like brake pad wear indicators.

[cclinard1]

If you have the tin can popping sound, then it's a pebble stuck for sure. I had this happen as well and it fell out on its on. Hasn't happened again.

[msan]

Originally Posted by cclinard1

If you have the tin can popping sound, then it's a pebble stuck for sure. I had this happen as well and it fell out on its on. Hasn't happened again.

Same for me. Eventually fell out and the tin can/ cow bell sound stopped

[F1FL]

Here's what it sounds like. Sounds awful and is driving me crazy.

Tried driving in circles to see what side it is coming from but I could not tell. Thoughts?

[JsL]

Originally Posted by F1FL

Here's what it sounds like. Sounds awful and is driving me crazy.

Tried driving in circles to see what side it is coming from but I could not tell. Thoughts?

Interesting that it only happens under deceleration. I think a pebble would make noise regardless of acceleration and deceleration. It would make noise when the car is moving.

Throw the car in Neutral when you hear the noise to see if it's drivetrain. Accelerate to 4th, decelerate, and as soon as you hear the noise, throw it in 'N'.

[F1FL]

Originally Posted by JsL

Interesting that it only happens under deceleration. I think a pebble would make noise regardless of acceleration and deceleration. It would make noise when the car is moving.

Throw the car in Neutral when you hear the noise to see if it's drivetrain. Accelerate to 4th, decelerate, and as soon as you hear the noise, throw it in 'N'.

Thanks for this suggestion. So when throwing it into neutral the sound immediately stops

[JsL]

Originally Posted by F1FL

Thanks for this suggestion. So when throwing it into neutral the sound immediately stops

Did you recently service your car or add a mod?

[F1FL]

Originally Posted by JsL

Did you recently service your car or add a mod?

Haven't modded it at all recently, the only thing I've done was changed the oil 1000 miles ago

[firstbimmer]

Had the exact same issue multiple times...always under deceleration, tin can scrapy sound, seems to come from rear wheel area, and walls/oyher cars reverberating the sound makes it most noticeable. Each time the sound lasted for 2-4 weeks, then disappeared on its own. Dealer has checked multiple times and has found nothing. My SA suggested that it is probably stuck pebble and that it is fairly common complaint.

[F1FL]

Originally Posted by firstbimmer

Had the exact same issue multiple times...always under deceleration, tin can scrapy sound, seems to come from rear wheel area, and walls/oyher cars reverberating the sound makes it most noticeable. Each time the sound lasted for 2-4 weeks, then disappeared on its own. Dealer has checked multiple times and has found nothing. My SA suggested that it is probably stuck pebble and that it is fairly common complaint.

Do you happen to know if yours stopped if it is thrown into neutral?

[Umi|all|day]

Mine made the same noise during this winter. Little
Pebbles must of gotten in the heat shields. It was coming from the rear driver side wheel (or maybe both I'm not sure) I only heard it during deacceraltion and in reverse haha.. but it went away and I haven't heard anything like that for a month or so now!

[F1FL]

Originally Posted by Umi|all|day

Mine made the same noise during this winter. Little
Pebbles must of gotten in the heat shields. It was coming from the rear driver side wheel (or maybe both I'm not sure) I only heard it during deacceraltion and in reverse haha.. but it went away and I haven't heard anything like that for a month or so now!

I'm just now worried its not a pebble because I would think even if I threw it into neutral the sound should still persist.. but it doesn't. Trying to get my car in for service on Monday...

[firstbimmer]

Originally Posted by F1FL

Do you happen to know if yours stopped if it is thrown into neutral?

I nevered tried putting it in neutral, but I did obsess over the sound each time. Since I just bought the car in august, the sound was driving me nuts. One time it happened after a dealer service and I was sure it couldn't be a rock....but then it would disappear right as I was stressing over it. Your video is the EXACT sound I get. I have put 12000 miles on since buying so I think the constant highway miles may help knock the pebbles out. One of the times my son was positive something had broke in the rear wheel, but again it disappeared after a couple weeks. Driving in the rain seems to help too.

[firstbimmer]

Originally Posted by Umi|all|day

Mine made the same noise during this winter. Little
Pebbles must of gotten in the heat shields. It was coming from the rear driver side wheel (or maybe both I'm not sure) I only heard it during deacceraltion and in reverse haha.. but it went away and I haven't heard anything like that for a month or so now!

Exact same situation as mine. I've realized it's just normal depending on the type of roads driven.