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bimmerlove335 bimmerlove335 is offline
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Default What causes this sound? SOLVED - 09-06-2017, 09:30 PM

Hi all,

I've really been enjoying fixing my car up lately and have been learning how to understand logs. Just wanted to say thanks to everyone on this forum, it's very informative.

So now to the subject matter, recently my car started making this really strange sound when stopped. It's like a squeaking or chirping sound. At first I thought I was my belt squeaking so I replaced the belt and tensioners which did nothing.

Then I heard that a pcv problem can cause the rear main seal to make noise so I replaced my pcv with the upgraded rb pcv, which didn't seem to help. And I didn't think that was the issue because removing the oil fill cap doesn't change the sound.

Finally I came to the opinion that I believe it's suspension or driveline related because it is most noticeable when stopped at a stoplight while holding brakes. The noise stops if I let go of the brakes to accelerate or if I put the transmission in neutral. Transmission is Auto FIY.
So I replaced my transmission mounts and the old ones looked like new when I removed them and it didn't fix the problem.

What do you think it could possibly be? I'm almost leaning towards motor mounts at this point but wondering what other possibilities there are. It definitely isn't coming from the front of the motor, that's one thing for sure.


Link to video:
https://m.youtube.com/watch?feature=...&v=4AAI8bp70jk

Thanks for any advice

Last edited by bimmerlove335; 09-09-2017 at 10:47 AM..
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E9xjake E9xjake is offline
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Default 09-06-2017, 11:38 PM

Quote:
Originally Posted by bimmerlove335
Hi all,

I've really been enjoying fixing my car up lately and have been learning how to understand logs. Just wanted to say thanks to everyone on this forum, it's very informative.

So now to the subject matter, recently my car started making this really strange sound when stopped. It's like a squeaking or chirping sound. At first I thought I was my belt squeaking so I replaced the belt and tensioners which did nothing.

Then I heard that a pcv problem can cause the rear main seal to make noise so I replaced my pcv with the upgraded rb pcv, which didn't seem to help. And I didn't think that was the issue because removing the oil fill cap doesn't change the sound.

Finally I came to the opinion that I believe it's suspension or driveline related because it is most noticeable when stopped at a stoplight while holding brakes. The noise stops if I let go of the brakes to accelerate or if I put the transmission in neutral. Transmission is Auto FIY.
So I replaced my transmission mounts and the old ones looked like new when I removed them and it didn't fix the problem.

What do you think it could possibly be? I'm almost leaning towards motor mounts at this point but wondering what other possibilities there are. It definitely isn't coming from the front of the motor, that's one thing for sure.


Link to video:
https://m.youtube.com/watch?feature=...&v=4AAI8bp70jk

Thanks for any advice
I believe if it were motor mounts you would feel the car shaking. I watched the video but it is a bit difficult to hear it. Does it effect drivability?? Or is it just something you hear?

Edit: I listened to it again and I guess I see what you're talking about. Sounds like some sort of rattle? See if you can make it do that while someone is outside of the car and have them pinpoint the area it comes from. Definitely hard to tell from a video though. Post this on the support section of the the website. It's found on the home page.


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Last edited by E9xjake; 09-06-2017 at 11:45 PM..
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bimmerlove335 bimmerlove335 is offline
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Default 09-06-2017, 11:49 PM

Quote:
Originally Posted by E9xjake
I believe if it were motor mounts you would feel the car shaking. I watched the video but it is a bit difficult to hear it. Does it effect drivability?? Or is it just something you hear?
Thanks for the reply.

Maybe I can take another video tomorrow so you can hear better. Does not seem to effect drivabillity as of yet but it's very annoying. It's loud enough that passengers and bystanders can hear it when stopped. Sometimes it almost sounds like a high pitched hum, other times is sounds more like a squeaky bushing.

The only thing I notice about motor mounts is a slight thud when shifting from neutral to drive or reverse. Not sure if that's normal or not, but I watched the engine when someone else shifted for me and it doesn't seem to move at all.
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E9xjake E9xjake is offline
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Default 09-07-2017, 12:15 AM

Quote:
Originally Posted by bimmerlove335
Thanks for the reply.

Maybe I can take another video tomorrow so you can hear better. Does not seem to effect drivabillity as of yet but it's very annoying. It's loud enough that passengers and bystanders can hear it when stopped. Sometimes it almost sounds like a high pitched hum, other times is sounds more like a squeaky bushing.

The only thing I notice about motor mounts is a slight thud when shifting from neutral to drive or reverse. Not sure if that's normal or not, but I watched the engine when someone else shifted for me and it doesn't seem to move at all.
Does seem strange. Does it hum when you're driving? I would assume it's drivetrain related if it does. But again I'd have a buddy stand outside, or even better yet see if you can get it to do it when you're in park in your driveway and find the noise from the outside and maybe get a video of it. It helps to know if it's under the car, front or rear, engine bay, etc. I'm not an expert but there are plenty people on here who are so if you can get us more info about it I'm sure someone can help


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Default 09-07-2017, 03:41 AM

That could be any little bit of trim etc in the cabin or engine bay vibrating at that specific frequency of the engine. Resonance. You could try checking what's in the glove box, door carriers. Put your finger on anything that moves.

Irritating


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E9xjake E9xjake is offline
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Default 09-07-2017, 06:01 AM

Quote:
Originally Posted by AWSAWS
That could be any little bit of trim etc in the cabin or engine bay vibrating at that specific frequency of the engine. Resonance. You could try checking what's in the glove box, door carriers. Put your finger on anything that moves.

Irritating
+1


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bimmerlove335 bimmerlove335 is offline
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Default 09-07-2017, 04:04 PM

Ok guys I took another video. Can't seem to get it to make the sound on park. Only in drive with the brakes on.

Check this out and let me know what you think. It gets kinda loud in this cideo and you can actually hear it, to me sounds like it's coming from outside the cabin somewhere.

https://m.youtube.com/watch?v=s4cMMW...ature=youtu.be
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bimmerlove335 bimmerlove335 is offline
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Default 09-07-2017, 04:22 PM

I can't hear the noise from the engine compartment at all. Sounds like it's coming from under the car, like transmission area
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E9xjake E9xjake is offline
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Default 09-07-2017, 06:45 PM

Quote:
Originally Posted by bimmerlove335
I can't hear the noise from the engine compartment at all. Sounds like it's coming from under the car, like transmission area
Yeah that definitely sounds like something loose I guess. That'll be hard to pinpoint


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austin austin is offline
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Default 09-07-2017, 10:29 PM

Does it ever make the sound in park? If so you could probe around with a stethoscope.

Otherwise it would help to narrow down the exact situations it does it in. For example if it doesn't do it in park, but does in drive it's unlikely to be something like an accessory or acc belt because it doesn't care about load, only RPM and sometimes engine acceleration- as in rapid rpm changes not acceleration of the car.
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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 08:17 AM

Quote:
Originally Posted by austin
Does it ever make the sound in park? If so you could probe around with a stethoscope.

Otherwise it would help to narrow down the exact situations it does it in. For example if it doesn't do it in park, but does in drive it's unlikely to be something like an accessory or acc belt because it doesn't care about load, only RPM and sometimes engine acceleration- as in rapid rpm changes not acceleration of the car.

If it makes makes it in park it's barely audible, and it rarely does. Usually, it'll make it in drive while stopped, as soon as I move to neutral/park or let off the brakes to accelerate the noise stops.

I'm wondering if maybe it's the torque converter or rear main seal making the noise. That'd suck!
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Default 09-08-2017, 08:19 AM

Does the sound change if you load it up at all, as in hold brake and give it a little gas? What about if you rev it in neutral? Kinda seems like a plastic on metal vibration, maybe check the under trays and heat shields, maybe clamps on exhaust or hangers.

You think you've heard all the noises an N54 can make, and then something new comes along...
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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 08:47 AM

Quote:
Originally Posted by Vorsprung_CJB
Does the sound change if you load it up at all, as in hold brake and give it a little gas? What about if you rev it in neutral? Kinda seems like a plastic on metal vibration, maybe check the under trays and heat shields, maybe clamps on exhaust or hangers.

You think you've heard all the noises an N54 can make, and then something new comes along...
I have the plastic valences all removed. It'd sure be nice if it was something simple.

Sound does not change by loading up the drivetrain with torque while holding brake, and the sound doesn't change if I rev in neutral.
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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 08:47 AM

Thanks for your help with this guys!!!! The other forum I use has offered very little advice.
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Default 09-08-2017, 10:17 AM

You mentioned you can't hear it from the engine bay, which throws out most of the other things I would think of. How many miles on the trans? Maybe do a fluid/filter change and examine the fluid and pan for anything suspicious, just to be safe.

Kinda tricky to stick your head under there to locate the sound since it has to be in drive to happen.
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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 10:27 AM

Quote:
Originally Posted by Vorsprung_CJB
You mentioned you can't hear it from the engine bay, which throws out most of the other things I would think of. How many miles on the trans? Maybe do a fluid/filter change and examine the fluid and pan for anything suspicious, just to be safe.

Kinda tricky to stick your head under there to locate the sound since it has to be in drive to happen.
105k on the trans as far as I know. I've had the car since 84k, don't know if the fluid was previously changed or not. I was thinking of changing it anyways so might give that a try
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Default 09-08-2017, 12:18 PM

To me that sounds like loose exhaust hardware. It may not be super loose, but if its loose enough to allow the parts to rub together it would make that type of noise. Re-tighten all connections, and check the lower ** mount locations. That's my take.. good luck.


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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 01:37 PM

Quote:
Originally Posted by shoepac11
To me that sounds like loose exhaust hardware. It may not be super loose, but if its loose enough to allow the parts to rub together it would make that type of noise. Re-tighten all connections, and check the lower ** mount locations. That's my take.. good luck.
Thanks for your advice!! Maybe I'll check that tonight!
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bimmerlove335 bimmerlove335 is offline
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Default 09-08-2017, 11:50 PM

Ok guys I figured it out.

Put th car up on ramps and got underneath. I had the engine running in park and listened very closely, could hear it very faintly. I could tell it was coming from around the exhaust area as people have suggested (good intuition guys) .

So i touched the bracket that the plastic undervalence attaches to under the transmission pan and sure enough that was it. The bolt that holds it to the body wasn't even lose, but the thing was loose enough to allow it to resonate at certain vibrations.

I'm so happy now. Thanks guys
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E9xjake E9xjake is offline
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Default 09-09-2017, 07:25 PM

Quote:
Originally Posted by bimmerlove335
Ok guys I figured it out.

Put th car up on ramps and got underneath. I had the engine running in park and listened very closely, could hear it very faintly. I could tell it was coming from around the exhaust area as people have suggested (good intuition guys) .

So i touched the bracket that the plastic undervalence attaches to under the transmission pan and sure enough that was it. The bolt that holds it to the body wasn't even lose, but the thing was loose enough to allow it to resonate at certain vibrations.

I'm so happy now. Thanks guys
That's probably a relief!


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bimmerlove335 bimmerlove335 is offline
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Default 09-09-2017, 07:49 PM

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Originally Posted by E9xjake
That's probably a relief!
Most definitely lol. I feel kinda dumb for not finding it sooner but definitely relieved.

You guys had good intuition. Thanks again for the help!
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