whining sound
 

hi Guys drove my car to first time since the winter and I'm hearing a high pitch whining sound when I'm cruising around 70mph and up.I only hear it when I press the gas pedal goes away when I release...any idea?:mad:

Lost my whining sound as a part of the divorce.... Do not suggest you do the same...

Where is the sound? Stereo? Engine compartment?

I'm hearing it towards the back the engine compartment

Alternator?

^ probable cause

Loose or dry belts?

if i it is the alternator shouldnt I hear the sound when the car is idling?

Could be the belt sensor roller, the plastic breaks up easy and the bearing can sometimes run dry and make noise.

I had a similar noise. Turned out the plastic intake piece that sits on the fan housing had a big crack in it. Does the whining increase and decrease with throttle and then go away at low revs? Relatively cheap fix.

yes exactly...I will check the fan housing....

Bump for update. What did you find?

didnt get a chance to check due to my work schedule I will today before the rain comes

Fan/shroud contact
 

It sounds like your fan is contacting the composite shroud. I had that problem a few years back and I was advised I needed a new shroud because it had become distorted because of the high heat in the engine compartment. Coincidentally, it first started making that singing noise when it was in the upper 90's that summer.

I'm glad I didn't spring for an expensive shroud replacement as late last year I had a new fan installed along with new bearings on the fan and alternator shafts. Evidently, the worn bearings had allowed for too much deflection via belt tension. Plenty of clearance now. My fan had apparently developed a few creeping hairline cracks on three blades and one day the centrifugal forces at a bit over 6k RPM caused two of them to fly off. It made a helluva noise, but luckily no damage to anything other than a couple of belts.

No idea why the blades developed the cracks other than from possible stress from the light contact with the shroud, but the broken surfaces showed a pretty even coating of engine soot that had crept in over time.

This thread is really timely for me. I'm still discovering my new 993 but it too makes a sort of whine. In my car, it very much sounds like a stereo ground loop/buzz, but the stereo is off and its definitely coming from the rear engine compartment.

I don't recall this sound in my C4S, so I was wondering if it had something to do with the Turbo. But after reading this thread, I wonder if it is something else. I'll need to do some more listening (acoustic research :)) and follow this thread.

Belt tensioning sensor? I just replaced this part.

ok guys...just had another look couldnt hear the sound with the engine lid open while revving by hand only pronunce from inside the car but I believe it could be the belt tensioner hear a little sound as the engine dies down.....

To confirm, just disassemble the sensor temporarily. Some others might pull it back but I think this is unsafe due to the rotating parts. If it is the sensor get it from Sunset Porsche.

I will try this tomorrow and let you....thanks

I had a silmilar sound on one of my cars this past fall. A fellow came over to look at it when it was for sale and commented on the whine, I said that it had just started doing that recently and I thought it was a belt or something but hadn't had a chance to investigate yet. He goes and puts his foot against one of the tailpipes and the sound stops! I was floored...he said it is a common 993 problem. I loosend the hanger and moved it over a 1/4 inch and the sound is gone :)

It is not a tensioner, just a roller sensor to sense if the belt is broken or not.

Pull the sensor away from the belt (when engine not running) and spin the wheel with your finger and see if you can hear any noise.

still cant figure where this sound is emitting from...only hearing it when the engine is warm at highway speed...help

finally found the problem...it was the air duct for the cooling fan it was busted:rockon: