WTF IS THIS SOUND https://www.youtube.com/watch?v=n2ox...ature=youtu.be

I have a 2003 G35 coupe 6spd manual and Im having a weird whining noise and whirring noise during revving on startup in neutral. Sound is unnoticeable and maybe unexistent when driving the car. Shifts smooth through all gears and doesnt sound like its coming directly from the motor. Sound is especially prominent when I rev it up and then let the rpms drop. sounds like a buzzing or whirring sound. I also have a high pitch squeak sound which i initially thought was a belt problem but now im thinking otherwise. I have narrowed it down to two guesses of my own. One, there is a bad pulley (likely the idler/tension pulley) whirring and causing belt slip and problems with idle. Two, my throwout bearing or entire clutch is bad and needs replacing. FYI: I bought the car with a stage 2 clutch apparently with low miles but it has always been incredibly stiff even for an aftermarket clutch.

Thanks for your help in advance!

-james

Sounds like some kind of exhaust rattle, make sure it's not touching anything else. The exhaust should be only touching the hangers, make sure a hanger isn't broken. If everything looks good remove the muffler section and shake it to see if there's something loose inside, you may have broken a baffle or some ******* might have put something into the muffler. Possibly a small crawled in and died, who knows.

Simplest to narrow down if its related to any of the pulleys is to remove the belt. That rattle noise does sound kind of exhaust rattly, but hard to tell.

If you have electric cooling fans, you can remove the mechanical fan pulley since it does nothing. I removed mine with 163k at the time and it had a fair amount of play in it and was noisy. For Sedans, only early-03 cars have a mechanical fan, everything after has electric fans, BUT they left the pulley there until late-06. I'm not sure if coupes ever had mechanical fans, my thinking is no, but not sure. You remove that bracket, and place an aluminum spacer between the timing cover and P/S bracket. The spacer is p/n 13298-4P10A, and you need a 1.5" shorter belt. I used a K060455, which worked, but I was almost out of adjustment on the tensioner, so I ended up putting on a K060450.