YaHoo!

Hi All-

I just picked up my new 964 and will post on that when I have pictures but when driving it home I heard a whistling sound I hope you all can help me diagnose.

I hear a whistling/squeaking sound maybe all the time faintly and it may increase with increased engine speed (its a little hard to tell because it is rather faint). It is most pronounced at 1,500 RPMs and I hear it most clearly inside the car. When I'm hovering over the engine it sounds like it may be coming from the right side (passenger side US). It happens regardless of if I'm in gear or not and whether moving or not.

I backed off the fan belt breakage indicator wheel to see if that was the problem but the sound persisted.

The engine and tranny were both just dropped and resealed.

Here are my thoughts on the potential culprits in no particular order- If one is not likely based on the info above then please let me know or if you have other suggestions.

-Chain tensioner inserted the wrong way (but a pro mech resealed the engine)
-fan bearing
-slipping belt (they feel tight)

Other thoughts or suggestions?

Thanks.

Mike

Rocket Rob

How steady is your idle? Sounds like it might be a vacuum leak.

PS: Congrats on the new car. Did I miss the photos?

JV911

bystanders whistling in awe

Mondrian

Shot bearings are known to make that sort of sound, probably need a pair of experienced ears to locate where.

HiWind

just a thought - check your CCU fan ... mine sounded like a whistle from the back left of the car from inside
... but its just the high pitched whine of the tired fan ... turn off the fan and close all vents and see if whistle disappears

ps ... did I also miss the pics?! :0

Navaros911

Disconnect the stereo and try again. In my car the stereo whistles through the speakers.

First try by turning it off completely. If you suspect it, then try disconnecting.

Outside the car there's all kinds of noises going on, but mostly the loud ones make it into the cabin.

So it may be generated in the cabin.

Navaros911

LOL!

robt964

>when I'm hovering over the engine it sounds like it may be coming from the right side

PS pump/belt ?

YaHoo!

Thanks for all the great responses. I'll add them to my list- it doesn't sound like it's coming from inside the cabin but I know how noises can throw themselves around.

The PS belt was just replaced and the pump rebuilt.

I'm suspicious that it is the bearing behind the motor fan- between the fan and the alternator. My mechanic made a good suggestion- he said get a few feet of tubing and put one end in my ear and then move the other end around the running engine to find where the noise is loudest.

Rocket Rob- thanks for the congrats- my introduction email is coming- I just need to get some decent pictures of the car. Vacuum is a potential culprit for sure but idle only bounces a tiny bit on starting and then is steady at ~800. Besides the intake manifold where are there other lines under a vacuum?

I can't wait to get into the car to figure this problem out! Hopefully I can get some car time in this weekend between kid & wife commitments!

jevvy964

Re-read yr post - you have my idea covered!

Laker

If you want to be a Porsche Doctor you need to look the part:
http://www.harborfreight.com/mechani...ope-69913.html

mojorizing

If you suspect it's one of the bearings driven by the belts, take each belt off one at a time and listen up. It's worth the time because when the fan/ alt bearing goes, sometimes it's not pretty. Be sure to use the proper triple box tool to hold the alt shaft.

YaHoo!

Perfect and at a Habor Freight price too! Thanks Laker.


Exactly what my mechanic suggested. The outside belt is the alt belt so I'll disengage that to see if the sound happens at a different frequency based on the different rpm. Thanks.

YaHoo!

I've narrowed the options a bit. Took off the outside belt, which is actually the compressor belt, and the slight squeak persisted. Put water on all the belts and the noise didn't change. So belts and compressor bearings are fine.

I am certain the noise is coming from the engine and not the cabin and it varies with engine speed.

I need to get a stethoscope but am now suspicious of either the PS pump (albeit it was just resealed but perhaps there's a bad/dry bearing in it) or the bearing between the motor fan and alternator. It is a slight squeal so I'm not really worried about it but would be good to diagnose it early if it is a problematic bearing.

The hunt continues.

ThomasC2

My suggestion is the fan belt sensor. If the bearing to the little plastic wheel is worn it can make a sound as yours. Push it away from the belt with a zip tie and try. I had this in my car.

Thomas