Unknown noise

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Nov 10, 2018 | 06:10 PM

ajd3rd

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Instructor

Joined: Feb 2004

Posts: 126

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From: Bloomingburg NY

Unknown noise

I'm trying to find the source of this noise

. It seems louder underneath the car. I'll be able to get under it tomorrow but I was hoping someone could give me some ideas based on the noise. It's a banging, clanking type noise and is directly related to rpms.

Any ideas would be greatly appreciated!

Nov 10, 2018 | 06:26 PM

3D-Aircrew

Melting Slicks

Joined: Nov 2007

Posts: 2,830

Likes: 147

From: Gainesville FL

Quote:

Originally Posted by ajd3rd

I'm trying to find the source of this noise Noise. It seems louder underneath the car. I'll be able to get under it tomorrow but I was hoping someone could give me some ideas based on the noise. It's a banging, clanking type noise and is directly related to rpms.

Any ideas would be greatly appreciated!

If it's coming from under the car, take a look at the exhaust system to see if the mufflers are on their hangers and not touch the frame anywhere. Also it could be the catalytic converter went **** up ... all broke up inside rattling.

Last edited by 3D-Aircrew; Nov 10, 2018 at 06:27 PM.

Nov 10, 2018 | 06:49 PM

Jitsu

Racer

Joined: Jul 2007

Posts: 383

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From: Tulsa, OK

Quote:

Originally Posted by ajd3rd

I'm trying to find the source of this noise Noise. It seems louder underneath the car. I'll be able to get under it tomorrow but I was hoping someone could give me some ideas based on the noise. It's a banging, clanking type noise and is directly related to rpms.

Any ideas would be greatly appreciated!

I doubt it is exhaust related if the noise frequency increases with RPMs. I have been going through the same thing on my LT4 and you will hear a host of possibilities -- exhaust leak, fuel injector, stuck lifter, etc.. In my case it turned out to be a rocker arm that came loose.

Nov 10, 2018 | 07:29 PM

ajd3rd

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Instructor

Joined: Feb 2004

Posts: 126

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From: Bloomingburg NY

It's weird. Sometimes I don't hear it and at other times it's more pronounced. It's tough to tell when driving on the highway whether it quiets down or the road noise drowns it our. It seems louder during acceleration from 20-40 mph. I need to change the oil tomorrow so I'll run it when i have it up on jack stands and see if I can pinpoint it.

Thanks for the replies.

Nov 10, 2018 | 08:12 PM

billschroeder5842

Zen Vet Master Level VII

Joined: Mar 2016

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From: Southlake, TX

Sounds like exhaust to me. Your video was shot while the car was not moving so there is no drivetrain noise. My money is on exhaust.

Nov 11, 2018 | 10:28 AM

ajd3rd

Thread Starter

Instructor

Joined: Feb 2004

Posts: 126

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From: Bloomingburg NY

Update on noise

I jacked up the car this morning and ran it. I listened to it with a stethoscope and it seems the loudest when I touch the valve cover bolt above the #5 plug. I guess the next step is to pull of the valve cover. I haven't done that on the later c4s. Can I get away with just ticking in back on or should I go get a set of gaskets? If I run it with the valve cover off is that going to make a mess?

Thanks!

Nov 11, 2018 | 10:51 AM

ajd3rd

Thread Starter

Instructor

Joined: Feb 2004

Posts: 126

Likes: 3

From: Bloomingburg NY

Update #3

I also have a 19k mile 95 LT1 coupe as well as the 96 vert with them problem. I almost never drive it. I listened to the same area and I can also hear a tapping but it seems less pronounce. Now I'm unsure of the next step. Is it possible that a lifter could only make noise sometimes? At times the noise is more pronounced and it doesn't seem to be consistent. I'm doubting it's exhaust as it doesn't seem any worse when it's cold.

Any ideas would be greatly appreciated.