Hello everyone, I need your thoughts on this. (searched and looked at the threads on IMS sounds and steering pump noises, didn't find anything that addressed this noise)

2003 TT with 29K miles, not mine, yet. On a test drive everything was good, but after a few "full throttle pulls in the lower gears" I noticed a pronounced whining coming from the back. Idles around 900 with the sound loudest at 1000 to 1100 rpm and almost gone by 1400. Worst right after rawhiding and disappeared in the stop-and-go over the next mile or two. Oil pressure 3.5 or there abouts at idle.

No difference clutch in or out. Smooth clutch travel, no noise on deceleration in gear.

The sound is like an electric fuel pump, a buzzing/whining vibration, seemed to come somewhere from the back. Not present after a few more miles so when I listened under the boot, no joy. I'm taking it in for a PPI in a few days but wondered if anyone here has some ideas on the source.

I had a 944 until the whining from the right seat took it away. Long sad story, don't ask. But driving the 996 felt like old times. Any ideas?

Regards, David

 

I think someone had an issue similar and it was a belt pulley. I think it was Larry (landjet) but it has been a while...

 

https://www.6speedonline.com/forums/...pump-well.html

 

The pulley sounds like the pump. Take the airbox out and listen to it.

 

Would either of these be noticable only when very hot? A disappear when at a more "normal" operating temperature?

I guess an early failure mode would be noise only when run near redline?

Thanks for the thoughts.

 

The pulley is right below the PSP and the noise is disguised with the air box in. If it's the same problem I had, you can only hear it at lower rpm's before the engine noise drowns it out. Does the whine coincide with rpm's? The pulley is pretty cheap, can't remember the cost now. I didn't do the work so don't know what is involved to change it. My tech originally diagnosed the noise as the PSP and I paid to change it with no resolution. Changing the pulley fixed it.

 

Yes, the frequency (speed of buzz) increases with rpm until it goes away at about 1400 rpm.

It had resolved completely by the time I got to where I could stop and pop the hood to listen to the engine.

Not sure why it would be intermittent and only following high-rpm runs. Could be an early failure sign I guess.

Thanks for the info. I hope the mechanic for the PPI knows what it is. If I can reproduce it on the drive over I'll pull a sound file and post what the mech says about it.