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What is this rattling sound?

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Old Aug 18, 2013 | 08:47 PM
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Default What is this rattling sound?

It's not internal I'm pretty sure. The sound comes and goes, usually on deceleration while downshifting or right after heavy acceleration.

Driving me insane.

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Old Aug 19, 2013 | 06:51 AM
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So does it only happen after you hit the throttle? I don't think it is a heat shield since the ticking follows the rpms. Are you sure it is not inside the head? The noise has a very metallic sound to it. I would pull the valve cover and check to make sure all of the rockers are torqued down properly.

I had a similar noise but it didn't have as much "ring" as yours does but mine was all the time. Ended up having some bent pushrods.
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Old Aug 19, 2013 | 07:23 AM
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Yea I'd pop that valve cover...
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Old Aug 19, 2013 | 10:50 AM
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Originally Posted by Streetlegal?
So does it only happen after you hit the throttle? I don't think it is a heat shield since the ticking follows the rpms. Are you sure it is not inside the head? The noise has a very metallic sound to it. I would pull the valve cover and check to make sure all of the rockers are torqued down properly.

I had a similar noise but it didn't have as much "ring" as yours does but mine was all the time. Ended up having some bent pushrods.
It happens at random intervals. For example, this morning on the way to work it never did it once. But when I left to my first appointment of the day, it started doing it.

The reason I don't think it's in the head is because I put a screwdriver up to it, and revved the engine and listened for the sound, and I hear nothing coming from the head except a really smooth "operating" sound.

It almost sounds like maybe the material in the cat is loose, or like there are quarters in my exhaust. Idk.
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Old Aug 19, 2013 | 11:48 AM
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Originally Posted by StryfeS13
It happens at random intervals. For example, this morning on the way to work it never did it once. But when I left to my first appointment of the day, it started doing it.

The reason I don't think it's in the head is because I put a screwdriver up to it, and revved the engine and listened for the sound, and I hear nothing coming from the head except a really smooth "operating" sound.

It almost sounds like maybe the material in the cat is loose, or like there are quarters in my exhaust. Idk.
What I meant was it will only happen as the engine slows down in rpms after you have hit the throttle but not consistently timed. For example, it will not make the noise if the engine is increasing in rpms just when it is decreasing.

I wouldn't think a heat shield would make that sound though since it seems to be rpm dependent. I would really pull the valve covers and just check. It's a really simple job and would probably take you an hour from start to finish.

If you are willing you could start the car and go under it and see if you can find where the sound is coming from. Or just grab a small diameter pipe, maybe 1/2" and use that as a stethoscope so that you can find where the general area of the problem is. Don't use a screwdriver.
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Old Aug 19, 2013 | 08:11 PM
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Originally Posted by Streetlegal?
What I meant was it will only happen as the engine slows down in rpms after you have hit the throttle but not consistently timed. For example, it will not make the noise if the engine is increasing in rpms just when it is decreasing.

I wouldn't think a heat shield would make that sound though since it seems to be rpm dependent. I would really pull the valve covers and just check. It's a really simple job and would probably take you an hour from start to finish.

If you are willing you could start the car and go under it and see if you can find where the sound is coming from. Or just grab a small diameter pipe, maybe 1/2" and use that as a stethoscope so that you can find where the general area of the problem is. Don't use a screwdriver.
I'll pull the valve covers this weekend when I have some time.

Yeah you're probably right on it not being the heatshield.

Any chance it's the AIR pump(I've read some where on here that LS1's have an air pump that warms up the cat or something.)?
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Old Aug 19, 2013 | 08:38 PM
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Originally Posted by StryfeS13
I'll pull the valve covers this weekend when I have some time.

Yeah you're probably right on it not being the heatshield.

Any chance it's the AIR pump(I've read some where on here that LS1's have an air pump that warms up the cat or something.)?
No idea on the air pump. I deleted all that crap
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Old Aug 20, 2013 | 10:35 PM
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Any input from any other fresh minds before I pull off the valve cover?
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Old Aug 21, 2013 | 08:28 AM
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It's not the air pump, that only comes on during start up to warm up the CATS and then it goes away.
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Old Aug 21, 2013 | 12:15 PM
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Originally Posted by StryfeS13
Any input from any other fresh minds before I pull off the valve cover?
Pulling the valve covers is a very easy task so it's not like it's the end of the world But I would assume it is something in there.
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Old Aug 21, 2013 | 12:43 PM
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Sounds like the A.I.R check valve on the driver's exhaust manifold.

Russ Kemp
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Old Aug 21, 2013 | 03:25 PM
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There is a T fiting that is located behaind ur intake mostly to the driver side it connect ur vacume lines this T fitting tends to melt some times and it will cause the metalic noise. I had same issue before . U might wana check if its leaking ..
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Old Aug 21, 2013 | 10:32 PM
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Found it. It was a check valve shaking around in some egr or air valve on the drivers exhaust manifold.
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Old Aug 21, 2013 | 10:33 PM
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Russ K wins the prize for the correct answer!!
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Old Aug 22, 2013 | 02:46 AM
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Exhaust leak??
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