996 3.4 Engine noise

[bababoom]

Im picking up a 996 this weekend.
Few jobs need doing to it one of witch is there is like a wining noise bearing noise when the engine is revved.
I thinking maybe alternator bearing or water pump?
Is there anything else this could be is it a conman fault?

[peterg1955]

Add to those two: idler pulleys

[anonymous-user]

Almost certainly the belt tensioner and two idler pullies - mine does it.

Easy way to check: Remove the belt and spin them by hand - if they're anything but completely smooth and silent, they're the culprit. Do the same with the alternator, PAS pump, A/C clutch and water pump..

[bababoom]

Ok is it much of a job? Not picked the car up yet so no idea how much room is in there. Im guessing the air box will have to come off and wheres the best place to get the pulleys?

[anonymous-user]

Airbox is one bolt, a hose clip onto the throttle body and the MAF sensor plug (and clips for the wire). There's decent enough room when you have the airbox out of the way.

Belt off with a 24mm (if I remember) spanner on the tensioner to retract it and slide the belt off the pullies.

Then twiddle each pulley by hand.

Refit belt - remember to refit it in the same direction of rotation so mark it, or ensure the side facing out from the engine faces out etc.

Oh, and bloody well enjoy that 996 Welcome to the club!

[marky911]

As said, the 3 pulleys (1 tensioner, 2 idlers but they're identical) are a common fault.

Follow the steps above and if the bearings are showing signs of wear you have two options. Either buy 3 pulleys at about £60-£80 each (depending on if you hit lucky price wise) or press out the old bearings and renew them.

I'm half way through doing mine. Preventative rather than necessary.
The bearings are out and the pulleys are at the powder coaters. My bearings and new belt are here ready to go back on.

These are the bearings. £18 each.

http://www.bearingbasement.com/product/bearings/32...

PS Mask the centre bore when painting or powder coating as your bearings are a precise fit obviously.

Edited by marky911 on Friday 25th August 17:04