CamaroRS91x

Ever since I got my camaro, there's been a nasty rattling noice at idle. I could never put my finger on it, but I thought it had to be something on the serpentine belt. So the other day, I took my car to the shop to get a starter re-installed that they screwed up. They told me it was the water pump bearings. So a couple days ago, I replaced the water pump.

THERE'S THAT DAMN RATTLING AGAIN!!!! whenever I idle, it sounds like a bunch of marbles being rolled around in a metal pan.....It also definitely sounds like it's coming from the front of the engine bay where all of the pulley's are.

My girl's 89 RS has the exact same noice and so do a couple of my other friends' with thirdgens. Anyone got any experience with this?!

Thanks!

ShiftyCapone

iTrader: (7)

Are you sure the engine is not knocking? Your description sounds like it to me. I would check your timing and maybe bump up your ocatne a bit the next time you are at the pump.

CamaroRS91x

hey thanks for the reply man,

No I realllly don't think it is. It only happens sometimes and in odd intervals. and I use 89 octane so :/ It definitely sounds like a bearing of some sort.

Stekman

Knocking is REAL hard to confuse with a marble in a can type of sound. Either you hear the marbles or you hear a dull thunking. If it's marbles, I would say detonation.

Just out of curiousity, hand rotate the engine to TDC according to the timing marks. Once at TDC, remove the distributor cap so you can view the rotor. Now rotate the engine backwards so you can see the rotor rotate in the opposite direction. The responcse between you rotating backwards and the rotor turning should be almost instantaneous.

swerve-driver

Idler bracket/pulley
Power steering pump
AIR pump or
Altenator.
Crank Pulley loose(?)
Look for rust or dust buildup to help determine which one it is-
I'd start with the idler pulley-
Best-
S-D

CamaroRS91x

idler pulley = ?

lol

JokerRS

try taking the belt off and run it for a few seconds and see if the noise goes away. If so try turning over your accesories and see if they seem normal.

swerve-driver

Excellent idea.


The idler assembly is the thing that tensions the belt.

ShiftyCapone

iTrader: (7)

I wouldn't do this very long. It may be easier to take the belt off, leave the car off and then turn the pulleys and yank on the bracket. No motor noise to interfere along with damage prevention to the motor. I still suspect timing. Out rule that first before you do any more harm.

Pablo

iTrader: (1)

have any of you ever heard a motor knock at idle?

lets see a show of hands..

anyone?


one of your accessories probably, AC compressors tend to make that noise, is your AC on when you hear it?

MY-92-RS

iTrader: (3)

I just had my alternator rebuilt {rear bearing failed} the way it was squealing you would think I had a vacuum leak sounds in the engine compartment can be misleading
Now I have a 145-amp alternator and NO vacuum leak!!
:lala:

ShiftyCapone

iTrader: (7)

My car would knock at idle when I had a serious timing problem 4 or so years ago. An old company vehicle I used to drive (4.3 TBI) would knock at every sinlge rpm including idle. It was shot, but ran. Cars that diesel when shut off are also knocking at idle.

JokerRS

A few seconds isn't very long.

If I was doing it I would have someone else start the car so it wouldn't take as long to start and stop.