help me identify this noise please

[Danishp97]

Hello guys, posting in the wrong forum because i guess someone here in might have a solution. My car is a M6 GC

One video is driving and decelerating
And other two are standstill revs holding it at 1000-1200 rpm.

Is this the wastegate rattle or heatshield? Car has vrsf catless downpipes along with akrapovic exhaust. The standstill rattling has started since a few days and everytime i drive around cruising it sounds like a bag of nails. It’s super embarrassing. Anyone in here?

Video link -

https://youtube.com/shorts/U1ecv8oAcy4?feature=share

https://youtube.com/shorts/pMpEyrcLoNA?feature=share

https://youtube.com/shorts/6lDgDM6IvVY?feature=share

Incase anyone is not able to view from the link here the videos are named ‘Wastegate rattle m6’ ‘heatshield or wastegate?’ ‘Wastegate rattle’ on YouTube. Looking for advice. Thanks in advance.

[TopJimmy]

Damn that sucks. To me I t sounds like something broke loose inside your exhaust, not wastegates. Have a buddy listen (sorry for his ears, you owe 2 beers) to identify if this is under hood, middle of car, or rear section. Then if you have no jack, drive 2 tires up a driveway onto the curb to lift one side up (the side with exhaust). Now after letting things cool you can wiggle under the car and thump around with a fist to find the rattle.

[Danishp97]

Originally Posted by TopJimmy

Damn that sucks. To me I t sounds like something broke loose inside your exhaust, not wastegates. Have a buddy listen (sorry for his ears, you owe 2 beers) to identify if this is under hood, middle of car, or rear section. Then if you have no jack, drive 2 tires up a driveway onto the curb to lift one side up (the side with exhaust). Now after letting things cool you can wiggle under the car and thump around with a fist to find the rattle.

It’s not from the rear, more prominently under the car front side (could say between under the hood and under the car)

[dezzracer]

I would take to dealer. Yea I know the stealership. But they will identify and fix quickly. No headaches or chasing ghosts is worth it sometimes.

[TopJimmy]

Do your downpipes have flex sections? If yes, look there first. Otherwise you need to check your brackets. The heat shields usually don't come loose all of a sudden.

[Danishp97]

Originally Posted by TopJimmy

Do your downpipes have flex sections? If yes, look there first. Otherwise you need to check your brackets. The heat shields usually don't come loose all of a sudden.

No idea as i got the car preowned with all the mods done. Not sure if vrsf catless pipes have flex sections

[spidy512]

Just throwing darts here. I need to listen with headphones.

I looked up the dp's, and they do not have a flex section. But do have a rather large slip fitting.

The noise does seem rpm dependant, so that would lead me to think wastegate (I have the S55 one at 2k). I also leam that way as the catless dp's I woul think would amplify any wastegate/turbo rattles. Your turbos sit in the middle of the top of the motor (hot turbo set up) so the wategates should be eaisly accessable.

I agree with TJ that heat shields just coming loose seems odd, but I am not familair with the shield arramgent in your car, so possibly there is a piece that rattles at the right frequency. It reminds me of Subaru days and the rediculous rattles you would get from the varios cheap shileding. I would start under the hood and follow the dp's from top to bottom to see if whomever istalled these things made sure eveything was clear.

As TJ said, if you have the ability spend some time with friends poking around the car do so. Do you have access to a lift? or at least a way to jack it up and get under the engine area?

If not, as others said, take it to the dealer or reputable indy and let them poke around.

Also, don't be embarrased. I can think of a million other things to be embarrassed about. You are driving an M6. Most won't notice the noise...

Good luck and keep us posted!

josh

[Danishp97]

Originally Posted by spidy512

Just throwing darts here. I need to listen with headphones.

I looked up the dp's, and they do not have a flex section. But do have a rather large slip fitting.

The noise does seem rpm dependant, so that would lead me to think wastegate (I have the S55 one at 2k). I also leam that way as the catless dp's I woul think would amplify any wastegate/turbo rattles. Your turbos sit in the middle of the top of the motor (hot turbo set up) so the wategates should be eaisly accessable.

I agree with TJ that heat shields just coming loose seems odd, but I am not familair with the shield arramgent in your car, so possibly there is a piece that rattles at the right frequency. It reminds me of Subaru days and the rediculous rattles you would get from the varios cheap shileding. I would start under the hood and follow the dp's from top to bottom to see if whomever istalled these things made sure eveything was clear.

As TJ said, if you have the ability spend some time with friends poking around the car do so. Do you have access to a lift? or at least a way to jack it up and get under the engine area?

If not, as others said, take it to the dealer or reputable indy and let them poke around.

Also, don't be embarrased. I can think of a million other things to be embarrassed about. You are driving an M6. Most won't notice the noise...

Good luck and keep us posted!

josh

Thank you so much for your detailed reponse. I really appreciate. I bought this car used and it had the Wastegate rattle since then. It’s only the standstill rattle that started after the bmw dealership here changed my suspension bushes. I have booked into an indy for inspection on lift, will keep you posted.

[Danishp97]

Originally Posted by spidy512

Just throwing darts here. I need to listen with headphones.

I looked up the dp's, and they do not have a flex section. But do have a rather large slip fitting.

The noise does seem rpm dependant, so that would lead me to think wastegate (I have the S55 one at 2k). I also leam that way as the catless dp's I woul think would amplify any wastegate/turbo rattles. Your turbos sit in the middle of the top of the motor (hot turbo set up) so the wategates should be eaisly accessable.

I agree with TJ that heat shields just coming loose seems odd, but I am not familair with the shield arramgent in your car, so possibly there is a piece that rattles at the right frequency. It reminds me of Subaru days and the rediculous rattles you would get from the varios cheap shileding. I would start under the hood and follow the dp's from top to bottom to see if whomever istalled these things made sure eveything was clear.

As TJ said, if you have the ability spend some time with friends poking around the car do so. Do you have access to a lift? or at least a way to jack it up and get under the engine area?

If not, as others said, take it to the dealer or reputable indy and let them poke around.

Also, don't be embarrased. I can think of a million other things to be embarrassed about. You are driving an M6. Most won't notice the noise...

Good luck and keep us posted!

josh

Just a doubt. People on youtube and other Facebook forums have fixed the wastegate rattle by tightening the arm or by fixing a spring on the arm to create tension, would that spoil the functioning of turbo in any way? Also if this noise is ignored, will it spoil the turbos?

[spidy512]

Originally Posted by Danishp97

Just a doubt. People on youtube and other Facebook forums have fixed the wastegate rattle by tightening the arm or by fixing a spring on the arm to create tension, would that spoil the functioning of turbo in any way? Also if this noise is ignored, will it spoil the turbos?

I have seen those fixes before, and to he honest I am not totally sure of the outcomes of those fixes.

With that said, I think many of those fixes should work fine, as along as they do not impede the wastegate actuation. My only concern (and why I have not bothered to fix) is I do not want to create a potential issue by introduscing a fix that has the potential to create too much of a restriction on the wastegate actuation. That can lead to bad things motor wise.

As far as letting it go, no I don't think it will cause issues. I am of the belief that the rattle from our turbos is a "feature" less of an actually issue. But for some the noise is unbearable, so off you go to fix it. This is of course subjective.

in the meantime, enjoh the car and lean on others locally to help you narrow it down. Let us know what you find.

josh

[Danishp97]

Originally Posted by spidy512

I have seen those fixes before, and to he honest I am not totally sure of the outcomes of those fixes.

With that said, I think many of those fixes should work fine, as along as they do not impede the wastegate actuation. My only concern (and why I have not bothered to fix) is I do not want to create a potential issue by introduscing a fix that has the potential to create too much of a restriction on the wastegate actuation. That can lead to bad things motor wise.

As far as letting it go, no I don't think it will cause issues. I am of the belief that the rattle from our turbos is a "feature" less of an actually issue. But for some the noise is unbearable, so off you go to fix it. This is of course subjective.

in the meantime, enjoh the car and lean on others locally to help you narrow it down. Let us know what you find.

josh

Exactly my thoughts. All I’m bothered about is the standstill rattle that is also there when coasting at parking speeds. Im hoping positively this is something as little as something loose on the dp fitting. I wouldn’t bother fixing wastegate rattle too. Guess its two different noises mixing up for me. Will keep you posted. Cheers from India 👍🏻

[Danishp97]

Originally Posted by spidy512

I have seen those fixes before, and to he honest I am not totally sure of the outcomes of those fixes.

With that said, I think many of those fixes should work fine, as along as they do not impede the wastegate actuation. My only concern (and why I have not bothered to fix) is I do not want to create a potential issue by introduscing a fix that has the potential to create too much of a restriction on the wastegate actuation. That can lead to bad things motor wise.

As far as letting it go, no I don't think it will cause issues. I am of the belief that the rattle from our turbos is a "feature" less of an actually issue. But for some the noise is unbearable, so off you go to fix it. This is of course subjective.

in the meantime, enjoh the car and lean on others locally to help you narrow it down. Let us know what you find.

josh

Hi. I noticed one thing that the standstill rattle only happens when the car is in Neutral and revs are held at 1000 -1100 rpm. If i slot in D and keep brake on foot and rev to 1000-1100 it does not rattle.

[TopJimmy]

Pull off your intakes and CP (rags in holes) to make hand room and then check the wastegate arms for play. If they're loose you've a place to start investigating, and if they're tight you've ruled it out (mostly). You can also thump on the heat shields to see if the rattle is there.

[spidy512]

Originally Posted by Danishp97

Hi. I noticed one thing that the standstill rattle only happens when the car is in Neutral and revs are held at 1000 -1100 rpm. If i slot in D and keep brake on foot and rev to 1000-1100 it does not rattle.

Another guess, but the car vibrates more when NOT in gear. When the drivetrain is engaged with power the vibrations are dampened, so less or no noise.

At this point I think you need to get the car in the air or on a lift. Have a buddy push the gas pedal while your under the car, etc. We can keep guessing, but being able to pinpoint the location should be the focus.

Forgot to ask, have you popped the hood and gassed it? If so does it allow you to hear it any better?

I am going for a drive in mine later, I will pay more attention tot the rattle....

josh

[Danishp97]

Originally Posted by spidy512

Another guess, but the car vibrates more when NOT in gear. When the drivetrain is engaged with power the vibrations are dampened, so less or no noise.

At this point I think you need to get the car in the air or on a lift. Have a buddy push the gas pedal while your under the car, etc. We can keep guessing, but being able to pinpoint the location should be the focus.

Forgot to ask, have you popped the hood and gassed it? If so does it allow you to hear it any better?

I am going for a drive in mine later, I will pay more attention tot the rattle....

josh

I can hear it if i pop the hood near the firewall and also below the driver and passenger cabin under the car.. will be taking it on lift middle of this week