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Exhust Maifold Quacking at Me


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james245
New User

Nov 24, 2017, 12:32 PM

Post #1 of 5 (270 views)
post icon Exhust Maifold Quacking at Me Sign In

2005 Chevy Malibu
120K

https://vocaroo.com/i/s1SsBMAN1OUV

(Link goes to mp3 file recording of engine.)

It sounds like ducks to me! Could be a rubbing sound. Recording device is located directly over exhaust manifold cover @ rear of engine between engine and firewall. It is not serpentine belt (my first thought) and both alternator and water pump are in front of engine. It could be something underneath manifold or emanating from engine itself but it doesn't sound like it comes from within engine. The engine sound in file sounds normal. It usually--but not always--goes away after engine idles for 15-20 minutes and the sound is much worse when engine is cold. It is difficult to hear when car is in gear so I'm not sure if it transmission related or not.

Any insight is welcomed.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Nov 24, 2017, 2:11 PM

Post #2 of 5 (261 views)
Re: Exhust Maifold Quacking at Me Sign In

Sounds like a dry bearing is something, possibly the alternator.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



james245
New User

Nov 25, 2017, 11:52 AM

Post #3 of 5 (236 views)
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In Reply To
Sounds like a dry bearing is something, possibly the alternator.

Thanks for taking the time to reply. It is not the alternator, that is in the passenger side front along with the serpentine belt. I have done some more testing and here is what I have found. I put the transmission through all the gears twice and the noise does not change at all so I don't think it is that. What does make the noise go away is increasing the rpms of the car above 1500 rpms. It sometimes comes back after reducing it to idle, sometimes not. Also, the sound is much stronger on the passenger side near the wheel than on the driver's side in the same location.

There is a metal box-like structure attached to the axle in the vicinity of where the sound could be coming from, I assume that this is where the driveshaft meets the axle but not sure about that. I just don't know where a dry bearing could be found. It is not the tire itself since the tire isn't moving.


(This post was edited by james245 on Nov 25, 2017, 11:53 AM)


Hammer Time
Ultimate Carjunky / Moderator
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Nov 25, 2017, 12:07 PM

Post #4 of 5 (222 views)
Re: Exhust Maifold Quacking at Me Sign In

Again, it sounds like a dry bearing in something so get a stethoscope and start touching it to things until you find it. We can't find it from here.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Nov 25, 2017, 1:32 PM

Post #5 of 5 (217 views)
Re: Exhust Maifold Quacking at Me Sign In

Quote OP ">It sometimes comes back after reducing it to idle, sometimes not.<"
Just ideas for now: Take the belt off only long enough WHILE this happens see if it's gone.
I'm just thinking of a couple plain rubber serpentine belts that couldn't be shut up for love nor money either right away new or used! One sounded like the whole vehicle was making noises from who knows where.
Most if sprayed with water or IMO better WD-40 shouldn't harm a rubber belt if belt 99% shut up for a short while totally.
Look at alignment of belt on the items including the harmonic balancer (bottom one) that's it's in line with all the others. Does it wobble on any pulley?
This is easy to rule out. If all good and really a bearing find it any which way as they don't heal and if the wrong one totally failed till something fell off unknown damage if a belt flapping around wildly,


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