Och

iTrader: (3)

So my car developed some soft of rattling and vibration at high engine RPMs. The vibration is felt though the whole drivetrain at high RPMs, at 5000 rpm it feels like something's about to fall apart.

When I disconnect the accessory belt, the noise stops, and the engine revs up smooth. So its most likely that its one of the pulleys/accessories, but they all spin smoothly by hand. Is there a way to detect which one is doing it?

Also, it seems to only happen when the car is in drive. At idle it seems to rev up smooth.

dvourthis

so you reved up the engine with the belt off in drive and it didnt do it? if it only does it when it is in drive then its prob a bad trans mount.

Och

iTrader: (3)

Well thats the confusing part, it only does it in drive, and only with accessory belt connected.

dvourthis

did you drive it up to 5000rpm with the belt off?

Och

iTrader: (3)

yeah and its absolutely smooth

dvourthis

insane but interesting. the way i figure out which pully is bad on my **** is wiggle the hell out of them to see if i can feel a clunk or something or with the belt on and engine running use a stethescope with long metal attachment to listen to each pully. if you cant figure it out like that youll have to take them off and inspect them. it can be any of them but the culprit is more than likey the tensioner. or the ps pump. or the idler. or the water pump.

Och

iTrader: (3)

Well, water pump is actually timing belt driven, and obviously it still spinning when accessory belt is off.

dvourthis

nix the water pump

Och

iTrader: (3)

Maybe its the harmonic balancer (crank pulley) itself? But then its still spinning with the accessory belt off, but obviously its spinning with no load on it.

dvourthis

if your harmonic balancer got f-ed up it would prob shake like you are talking with or with out the belt so ya i would nix that too. so whats left? ps, idler, tension, alternator? id have to go outside in the rain to look..

Och

iTrader: (3)

Alternator, PS, Harmonic balancer, AC, fan idler, tensioner idler, and another idler.

dvourthis

hmm so with the fan idler would the fan be non operational with the belt off? the fan itself would also need to be ruled out. ive seen idlers go bad but they usualy just make a lot of noise and not a lot of vibration. the tension could def be the culprit and would be easier to rule out than the alternator, ps pump, or ac compressor.

Och

iTrader: (3)

The fan setup is actually a flustercluck - its a fan with clutch that gets mounted onto the idler. I removed it from the idler to rule it out.

dvourthis

dang man sounds like you got a tensioner issue i would think.

LiCelsior

iTrader: (32)

sounds like u need a mechanics stethoscope to determine the problematic part.