2004 996tt x50 belt squeal
09-30-2011, 07:03 PM
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2004 996tt x50 belt squeal
belt squeal, and its elimination.Three videos showing my noise, its diagnose and cure.
Please comment. Hope this helps others.
Car in video is cold at start up, 2004 996tt x50 tip cab.
fist vid, http://youtu.be/Vaf0HplwAjk
2nd video http://youtu.be/NcEQ53t61X0
last one. http://youtu.be/-fnYaiychgw
Yes the engine seems noisy in video, it runs very smooth and quiet, for an x50,, it seems the camera makes every noise very loud when you get that close with a mic.
This belt was replaced by Porsche at the 60,000 service, old belt never made a noise the entire 60,000, the new belt started doing this after 2000 miles on it, tension with a belt tension gauge was ok, it appears some coating, maybe a belt dressing was on the belt, and a simple swipe of a brush on the pulleys and belt cleaned it off and now it is quiet, belt dressing is the next thing I will do to help preserve the belt, Ironically the old belt was in perfect condition, just old. This noise started after car was detailed, possible they sprayed engine with something although detailer says he never touched the engine.
As for Walters detergent, WD40 I would not spray this on a belt, it is a lubricant, although the extra slip might burn off what is making it slip, or, not really sure., doesn't seem like a good thing to do, the water actually is very little, it just allows you to confirm the belt is slipping.
Please comment. Hope this helps others.
Car in video is cold at start up, 2004 996tt x50 tip cab.
fist vid, http://youtu.be/Vaf0HplwAjk
2nd video http://youtu.be/NcEQ53t61X0
last one. http://youtu.be/-fnYaiychgw
Yes the engine seems noisy in video, it runs very smooth and quiet, for an x50,, it seems the camera makes every noise very loud when you get that close with a mic.
This belt was replaced by Porsche at the 60,000 service, old belt never made a noise the entire 60,000, the new belt started doing this after 2000 miles on it, tension with a belt tension gauge was ok, it appears some coating, maybe a belt dressing was on the belt, and a simple swipe of a brush on the pulleys and belt cleaned it off and now it is quiet, belt dressing is the next thing I will do to help preserve the belt, Ironically the old belt was in perfect condition, just old. This noise started after car was detailed, possible they sprayed engine with something although detailer says he never touched the engine.
As for Walters detergent, WD40 I would not spray this on a belt, it is a lubricant, although the extra slip might burn off what is making it slip, or, not really sure., doesn't seem like a good thing to do, the water actually is very little, it just allows you to confirm the belt is slipping.
Last edited by timmhaines; 10-03-2011 at 05:28 PM. Reason: add more
10-01-2011, 11:18 AM
#4
Race Director
belt squeal, and its elimination.Three videos showing my noise, its diagnose and cure.
Please comment. Hope this helps others.
Car in video is cold at start up, 2004 996tt x50 tip cab.
fist vid, http://youtu.be/Vaf0HplwAjk
2nd video http://youtu.be/NcEQ53t61X0
last one. http://youtu.be/-fnYaiychgw
Yes the engine seems noisy in video, it runs very smooth and quiet, for an x50,, it seems the camera makes every noise very loud when you get that close with a mic.
Please comment. Hope this helps others.
Car in video is cold at start up, 2004 996tt x50 tip cab.
fist vid, http://youtu.be/Vaf0HplwAjk
2nd video http://youtu.be/NcEQ53t61X0
last one. http://youtu.be/-fnYaiychgw
Yes the engine seems noisy in video, it runs very smooth and quiet, for an x50,, it seems the camera makes every noise very loud when you get that close with a mic.
Check the belt it has no sections of ribs missing. Check that it doesn't have a sharp edge which means the belt is rubbing and an accessory drive is misaligned due to excessive bearing wear. In my experience this will be the water pump but any accessory drive can cause the belt to mistrack.
Be sure to check the idler rollers and their bearings. One developed a 'dry bearing' noise on my 03 Turbo and was replaced. Had I ignored the noise the bearing might have developed enough friction to cause the belt to squeal.
Oh, never use water or WD40 on a serpentine belt. The belt is intended to run dry and free of any lubricates especially those that can attack the rubber of the belt.
Sincerely,
Macster.
10-02-2011, 06:40 AM
#5
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Did you inspect the belt for any signs of distress? The belt should need no attention of any kind if all is well. They are install and run and replace after so many miles (or time).
Check the belt it has no sections of ribs missing. Check that it doesn't have a sharp edge which means the belt is rubbing and an accessory drive is misaligned due to excessive bearing wear. In my experience this will be the water pump but any accessory drive can cause the belt to mistrack.
Be sure to check the idler rollers and their bearings. One developed a 'dry bearing' noise on my 03 Turbo and was replaced. Had I ignored the noise the bearing might have developed enough friction to cause the belt to squeal.
Oh, never use water or WD40 on a serpentine belt. The belt is intended to run dry and free of any lubricates especially those that can attack the rubber of the belt.
Sincerely,
Macster.
Check the belt it has no sections of ribs missing. Check that it doesn't have a sharp edge which means the belt is rubbing and an accessory drive is misaligned due to excessive bearing wear. In my experience this will be the water pump but any accessory drive can cause the belt to mistrack.
Be sure to check the idler rollers and their bearings. One developed a 'dry bearing' noise on my 03 Turbo and was replaced. Had I ignored the noise the bearing might have developed enough friction to cause the belt to squeal.
Oh, never use water or WD40 on a serpentine belt. The belt is intended to run dry and free of any lubricates especially those that can attack the rubber of the belt.
Sincerely,
Macster.
Having said that, of course your advice of checking for any missing ribs and inspection is sound, however if OP’s belt stopped squealing with just him putting some water on it, I think he doesn’t really have a problem.
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10-03-2011, 11:26 AM
#9
Race Director
I respectfully disagree and will defend my advice. Our belts squeal due to water and moisture getting onto them, then drying (wet, heat, dry - cycle). After all we do have gaps on top of our engine covers where water gets in easily. If a small squirt (½ second) of WD40 cures the squeal, you should not jump to dry bearings, misalignment and or faulty water pump conclusions. My Porsche tech (from Stuttgart OEM workshop) told me that I should use a small squirt of WD40 and that WD40 is in no way harmful to the belt. In my case it silences my brand new belt when it begins to squeal. I guess it depends on where you live. If you live in dry moisture free area your belt might not squeal, if you however live in a moisture rich area and have lots of rain or wash your car frequently, then the squeal will “attack you” no question about it. Now, how you deal with it, either by dismantling the water pump and attack the bearings or simply squirt on some WD40 is the choice everyone needs to make individually.
Having said that, of course your advice of checking for any missing ribs and inspection is sound, however if OP’s belt stopped squealing with just him putting some water on it, I think he doesn’t really have a problem.
Having said that, of course your advice of checking for any missing ribs and inspection is sound, however if OP’s belt stopped squealing with just him putting some water on it, I think he doesn’t really have a problem.
But the noise is shortlived -- just a squeek or two then silence -- and the noise is not present at any other time.
A properly functioning Turbo serpentine belt and this includes the pulleys and roller and tensioner that it comes in contact with should not need any dressing if it is making any noise beyond the brief noise it can make after a car wash or rain soaking.
It should instead receive the attention the noise clearly indicates it needs to find the true source of the noise and address this cause.
I've replaced the serpentine belt on my Boxster several times and the Turbo once (I had this done when the car was in for a noisy roller bearing and the labor was done under the warrantied labor to replace the noisy roller bearing) and neither car's belt made any noise before or after the belt change, save the Turbo which sometimes after a wash or much less often when exposed to rain will squeal a bit upon engine start.
A noisy belt, used or new, is not normal.
A belt should never need dressing. The belt works by the grip the v's of the ribs have with the v-grooves of the pulleys. The belt should grip and not slip and then release with no residual lingering grip. A dressing simply temporarily affects this grip with the result the belt likely slips but makes no noise. The dressing attracts dirt which can result in premature belt wear or since the belt is softer than the pulley material the dirt embeds itself in the belt rubber and acts as an abrasive belt while running. This can cause wear of the pulleys so that when the new belt is installed its grip with the pulleys is affected because the pulley v-groove forms are distorted due to wear.
I know various substances are recommended by some for belt dressings, substances ranging from of course WD40 to Ivory soap, even belt wax, but my experience with car and machinery belt drives is to use no dressing unless the belt maker or the machinery maker advises it. And except for leather belt drives -- I used to work with/on some old machinery -- I can't remember any V-belt or flat rubber belt requiring any dressing.
Sincerely,
Macster.
10-03-2011, 05:34 PM
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Sure the belts squeal from water getting on them. I hear this a bit every time I start the engine after washing the car, and sometimes if conditions are right after letting the car sit out in the rain.
But the noise is shortlived -- just a squeek or two then silence -- and the noise is not present at any other time.
A properly functioning Turbo serpentine belt and this includes the pulleys and roller and tensioner that it comes in contact with should not need any dressing if it is making any noise beyond the brief noise it can make after a car wash or rain soaking.
It should instead receive the attention the noise clearly indicates it needs to find the true source of the noise and address this cause.
I've replaced the serpentine belt on my Boxster several times and the Turbo once (I had this done when the car was in for a noisy roller bearing and the labor was done under the warrantied labor to replace the noisy roller bearing) and neither car's belt made any noise before or after the belt change, save the Turbo which sometimes after a wash or much less often when exposed to rain will squeal a bit upon engine start.
A noisy belt, used or new, is not normal.
A belt should never need dressing. The belt works by the grip the v's of the ribs have with the v-grooves of the pulleys. The belt should grip and not slip and then release with no residual lingering grip. A dressing simply temporarily affects this grip with the result the belt likely slips but makes no noise. The dressing attracts dirt which can result in premature belt wear or since the belt is softer than the pulley material the dirt embeds itself in the belt rubber and acts as an abrasive belt while running. This can cause wear of the pulleys so that when the new belt is installed its grip with the pulleys is affected because the pulley v-groove forms are distorted due to wear.
I know various substances are recommended by some for belt dressings, substances ranging from of course WD40 to Ivory soap, even belt wax, but my experience with car and machinery belt drives is to use no dressing unless the belt maker or the machinery maker advises it. And except for leather belt drives -- I used to work with/on some old machinery -- I can't remember any V-belt or flat rubber belt requiring any dressing.
Sincerely,
Macster.
But the noise is shortlived -- just a squeek or two then silence -- and the noise is not present at any other time.
A properly functioning Turbo serpentine belt and this includes the pulleys and roller and tensioner that it comes in contact with should not need any dressing if it is making any noise beyond the brief noise it can make after a car wash or rain soaking.
It should instead receive the attention the noise clearly indicates it needs to find the true source of the noise and address this cause.
I've replaced the serpentine belt on my Boxster several times and the Turbo once (I had this done when the car was in for a noisy roller bearing and the labor was done under the warrantied labor to replace the noisy roller bearing) and neither car's belt made any noise before or after the belt change, save the Turbo which sometimes after a wash or much less often when exposed to rain will squeal a bit upon engine start.
A noisy belt, used or new, is not normal.
A belt should never need dressing. The belt works by the grip the v's of the ribs have with the v-grooves of the pulleys. The belt should grip and not slip and then release with no residual lingering grip. A dressing simply temporarily affects this grip with the result the belt likely slips but makes no noise. The dressing attracts dirt which can result in premature belt wear or since the belt is softer than the pulley material the dirt embeds itself in the belt rubber and acts as an abrasive belt while running. This can cause wear of the pulleys so that when the new belt is installed its grip with the pulleys is affected because the pulley v-groove forms are distorted due to wear.
I know various substances are recommended by some for belt dressings, substances ranging from of course WD40 to Ivory soap, even belt wax, but my experience with car and machinery belt drives is to use no dressing unless the belt maker or the machinery maker advises it. And except for leather belt drives -- I used to work with/on some old machinery -- I can't remember any V-belt or flat rubber belt requiring any dressing.
Sincerely,
Macster.
Is it possible something was damaged or changed when the dealer replaced the belt, never had any noise till after the belt change?Bad belt? cleaning the belt seems to have eliminated the noise, seems strange I should even have to mess with a new belt, had a lexus that did this same thing SC430, changed belt and then had squeal, maybe the 60,000 on the old belt had made it softer? The noise is gone for now, I simply posted the water trick, so others wouldn't needlessly start replacing expensive parts.
10-04-2011, 02:44 AM
#11
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Sorry Macster, but not so. I am in a Porsche club Slovenia/Austria. Nearly all members with 996TT have this occasional squeal and it does not go away by itself. Once WD40 is squirted on it goes away for two to three months or even more – conditions dependant. It is a well known issue here in Europe and not necessarily a problem. If your car does not do it you are lucky. But again, Porsche Stuttgart technician (we are talking factory engineer) advised me to put on a squirt of WD40 and since it stops the squeal for months this is what I will keep on doing.
10-04-2011, 11:46 AM
#12
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When a belt squels and starts slipping, it very possibly can leave hot spots or scoring on the pulleys. Sometimes it only takes a little cleaning of the pulleys with the use of a fine grit sand paper on the tensioner surfaces. WD 40 is good for displacing water, but it will come back again! Belt dressing is a temporary fix.
10-10-2011, 07:11 PM
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looking close the brush worked as the new belt had sharper edges than my old pulleys which are smoothed very slightly and the squeal was from the very small air gap, after the quick brush, the noise has not come back at all. hope this helps others.
