Raise

iTrader: (31)

I noticed this since I picked up my car a few months back when the car was bone stock, so I know it has nothing to do with mods Ive done. At idle standing away from the car I can hear a faint metallic sound. It is hard to describe, but it sounds like a bunch of paperclips rattling around in a can. I thought it may be a cat, but I just put on longtubes and an offroad y-pipe. Also, I cannot hear it from inside the car, nor when i put my head under the hood. I can only hear it from backing away from the car a few feet and it sounds like its coming from under the hood or underneath, definitely from the front endthough.Ive done a bit of searching but havent come up with anything other than broken catalyst and clutch issues. I should add my car only has 20k miles on it and just has lid, fra, headers and catback. Anyway, any ideas fellas?

Raise

iTrader: (31)

nobody?

sjsingle1

iTrader: (1)

normal piston slap??

Big&Tasty TA

Well the Ls1 has reputations for having piston slap, but it should go away once the vehicle warms up. If it is still there once the vehicle is at operating temperature I would pop off the belt and start the car, Don’t run it for long, no more than 20 seconds, the point of this would be to eliminate any noises that can be coming from the things off the belt. If the noise is still there I would then look into the valve train. Pull off the covers and inspect the rockers and springs. If they are fine then I would continue searching the valvetrain, pushrods etc. There is a bulletin from GM on the ls1s having rocker arm failure. The needle bearings would go bad and the rockers would come apart. Hope this helped and good luck.

Bulletin Number #02-06-01-029

ls1 1990 VN

He said he can't hear it from under the hood or inside the car....Piston slap you sure can.

HVYMTL

Pilot bearing failure maybe? Mine made a lot of noise kinda like what you described before I pulled it with my clutch swap

Raise

iTrader: (31)

Its certainly not piston slap, I know what that sounds like. And Ive owned enough LS1s to know if it was valvetrain related. Im thinkin Big&Tasty is onto something with accessories. I will pull the belt and see if it goes away, and go from there. Any other ideas?

szalkerous

iTrader: (1)

Sounds like you have the same problem mine does.....

Does it go away if you turn your A/C on?

If so, A/C clutch bearing. I'm actually poking around right now looking for anyone else that's replaced one on here....

EDIT: Or there's an adjustment to the clutch.... a couple other threads on here detail it... I'm not sure which I'll need, but I'd think adjusting the clutch is a "free" fix if it works.... if not, a new clutch bearing...

EDIT AGAIN: A useful link I found in another thread: http://flashoffroad.com/Maintenance/...llyService.htm

Raise

iTrader: (31)

I will have to check to see if it goes away when i turn my ac on

00pooterSS

iTrader: (40)

Mine is currently doing the SAME thing, can barely hear it under the hood if at all and not at all in the car, but 5 to 10 feet away it is very noticeable, I traced it down the other day to my A/C tensioner pulley.

Pull the belts off and crank it, if the noise stops spin the pulleys and listen for the loud one.

I found mine using a stethescope but I know most people dont have those. If you know what your doing you can use a long screwdriver or pry bar to listen through and figure out which pulley it is.

But it's much safer to just pull the belts and crank it up.