What can it be? (Bad metallic rattle)

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xBa380

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Hey guys...

Just did the oil change on my brothers 2002 Grand Prix... Car is a POS with things always going wrong... Anyway... I did the oil change, snugged everything up and checked some of the fluids and all that.

Started the car, and there is some terrible metallic rattle that appears to be coming from the area with all the pulleys with the serpentine belt. At least I think that is the source. It is very loud and sounds like marbles bouncing around a tin can or something.

I can't pinpoint the location of the noise, which is why I am asking for some general help. I know its hard online without video/sound sample, but maybe somebody can help otherwise.

Probably taking it to the shop next week... It sounds bad. The noise increases when the engine is rev'd. Can't find anything loose under the hood that would rattle. It sounds more then a rattle though. I don't believe it has to do with the engine itself.

Oil change went good though
thumbsup2.gif


Thanks!
 
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The power steering is wacky now that I think of it. Eats up fluid and at times goes really stiff after you start it and turn the wheel. I don't know why he wont get it replaced...
 
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Usually thats a sign of "morning sickness" (stiff steering).That term has been around since the 1980 Citation and 1982 Celebrity.In other words,a worn spool valve that bleeds by until the fluid heats up.The leak is worn rack seals or worn pump bearing with the associated worn seal.
 
Disconnect the belt and try spinning the pulleys. The one in the video was a pulley tensioner assembly. My wild guess is alternator bearing gone bad. Check the voltage gauge for wild fluctuations.
 
If it's a very loud marbles sound it'll probable turn out to be wiped bearings in the water pump. Remove both belts and try to wobble the water pump pulley by hand. If it moves, well, time for a new pump. If that's not it spin each pulley by hand until you find the noise.

If you find no problem in the pulley bearings or any obvious problem with belt driven accessories, look for a tensioner that is swinging it's arm back and forth rapidly. It shouldn't be doing that and if it does, that could be the source of the noise. Even if that's the source of the noise that doesn't mean there's anything wrong with the tensioner itself as a tensioner can do this in response to a problem in the power steering, AC, or an incorrect length belt.

Look also for a cracked water pump or power steering pump pulley.

If the problem seems to be in the supercharger don't get too excited. With the 3800SC, it is not uncommon to have a worn bearing in the supercharger snout. A bad bearing in the snout will be far less expensive of a problem to repair than pretty much anything that could go wrong with the blower itself.
 
Is this supercharged? If it is my vote goes to the coupler in the supercharger snout. It's a $20-$30 part, not too hard to do, just a little time consuming. The bearings in the snout rarely go out as this coupler takes the beating as it is designed that way.
IF the sound IS coming from the top side right near the S/C snout i would look at this coupler. Google it
I had a GTP that started to make this rattle noise in the snout. It was the coupler. I'm pretty sure there is even a better/higher quality designed coupler now too.
 
Thanks guys for the suggestions. Will take a closer look next week if he didnt already take it somewhere.

And it is not the supercharger engine, just the normal V6.
 
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