CHRRRIS

When I turn my car on, there is an odd rattle noise coming from the motor.. I don't know how else to describe it other than it sounds as if there were a loose washer rattling against metal... I've looked around the entire engine bay and tried to pinpoint the sound but I just can't tell where it is coming from.

This usually happens when it is cold started then goes away when the motor gets warm and has been driven...
If I give it a rev it seems to go away, but then again I have TD's and it's hard to listen for it.
The car runs strong, has good oil pressure, gets up to temp fine, pulls hard...

Has anyone ever had something similar, or does anyone have any ideas of where a loose metal or steel piece could be rattling against something like this?

eseibel67

iTrader: (10)

Check your O2 sensors. Knock on the pipe close to the suspect O2 with your knuckles (on a cold engine of course). The shells may be loose.

youguessit

damn, hope its not a lifter. kinda sounds like a spray can being shaken up?

CHRRRIS

eseibel, I'll check that out when I get a chance thanks for the suggestion. (I keep the car in a parking garage and don't drive it too often so not sure when I will get to it).

youguessit, it is a very high pitch sound.. so not quite like shaking a spray can. maybe if you were to put a dime in a glass cup and shake that around? I don't have any glass cups here at school but I imagine it would sound similar lol

chrisdacarnut

iTrader: (1)

If it's an automatic car, it could very well be a cracked flex-plate. Happened on both of my LS1 cars. If you have a cracked flex-plate it will rattle like hell.

CHRRRIS

Yes it's auto. How can I check if it's the flex plate? I'm guessing I would have to get underneath the car and look around. I won't be able to do so until the week of Thanksgiving but will it be an obvious crack or is there somewhere specific to look?

1quickirocz

piston slap!! dont wory bout it just drive it and have a nice day!!

ae13291

iTrader: (8)

it could be piston slap or a bad lifter. i was going to say it can be a rocker arm that busted needle bearings but seems the sound goes away when you rev it?

1CAMWNDR

iTrader: (21)

+1 for Piston Slap.

JRracing

iTrader: (35)

How many miles are on the motor?

CHRRRIS

It doesn't sound like piston slap at all. Uploading a video now... *Engine has just over 111k miles

CHRRRIS

Here is a video from a little while ago I made for the exhaust, but listen close and you can hear the high pitch rattling, especially when I leave the rear of the vehicle and go around the side to the front.

Any ideas? I can make a better video next week if anyone would like, but I am also going to investigate this much further next week when I can actually get under the car.

http://www.youtube.com/watch?v=_3V5d...layer_embedded

CHRRRIS

Damn, now that there's a video nobody has any ideas?

1quickirocz

I think i hear what you are talking about but it is hard to tell. it sounds like the ac compressor clutch has too tight of a clearance. That is ofcourse if the car still has ac on it. if you have ac try turning it on so the compressor engages and see if it goes away then. if not that it kinda sounds like a pulley bearing. maybe idler pulley or tensioner? deff doesnt sound likke an internal engine or trans noise.

CHRRRIS

Yes it does have AC. Thanks for the suggestions, I'll check them out when I get a chance.

If I still can't find a solution after I check all this stuff I will try to get a better vid and/or take it to a performance shop to see if they can pin point it.

BAD2000TA

iTrader: (6)

I have this same noise, but can't find the source either. So, you're not alone! You described it perfectly - little washer rattling against something metal. Goes away after warm-up.

Nobody else??

CHRRRIS

It's something to do with the AC! Luckily I went over to a friends house when I got home for break and he noticed the sound from outside the car (can be heard over my TDs lol) and he had the exact same problem with one of his cars... I turned the AC on and it went away.

So, anyone know how to fix it?

*Edit: Anyone know how to replace the clutch and/or re-clearance it? I read you need a special tool, but can't find any write ups on this anywhere!

tdevil55

iTrader: (23)

I just fix a problem with that same sound. About a week and half ago, my camaro got flooded up to the crank, so the ac, and pulleys got wet and submerged, and when I cleaned the car and started it back up, it had that same kind of sound coming from it. I first got some spray lube and sprayed the pulleys and ac clutch down real good. The sound got better, but the noise was still there. Decided today to change my belts and checked my pulleys. First took off my main s-belt and started the car again to rule out any pulleys there. I also had spun them to make sure none were freezing or hard to turn. When I cranked the car, I still had the same noise. So took the ac belt off and spun the twp pulleys and the ac clutch. The idler pulley and tension pulley both are making noise and needed replacing. AutoZone had one in stock, so got that one on tonight. The difference in the sound was night and day. That may be your problem also. My camaro has 102k on the clock, so you may need a change on them. It’s also cheaper to try those first, only like $16 for a pulley and belts were not that bad either. Hope this helps some and that you find the problem, but also lube that clutch on the ac some, that will help it from rusting any more.