Belt sqeaks like MAD - Tilted Forum Project Discussion Community

starbum · 09-12-2003, 04:55 AM

The belt in my car (mazda 94 MX3) sqeaks alot. And its only when I start the car and for the first 30 seconds of my drive, depending on how much I abuse the gas pedal. Gets louder when I accelerate, then dissapears.

I've taken it to the shop, they've tightened the damn thing 7 times now. It works for about a week or so, then it sqeaks again. I took it back and they replaced the alternator. That worked for 2 weeks, then it sqeaked again. wtf is going on? They refuse to replace the belt itself because they say its perfect.... they say that it somehow loosens itself and that causes the sqeaking.

What could be causing the belt to sqeak? They also noted that the mounting bolts for the engine might be loose or broken. FUN.

weasel2112 · 09-12-2003, 07:11 AM

Go to the autoparts store and either replace the belt or get some stop squeak. Some belts new or old will squeak when you they are cold.

Scorps · 09-12-2003, 07:12 AM

All you need is a new belt

dailyjo2003 · 09-12-2003, 08:06 AM

New belt -or - take a bar of soap and rub it on the inside of the belt - that will stop the squeaking

shakran · 09-12-2003, 08:43 AM

And cause the belt to slip, and potentially break the belt down. Not a good idea. Just get a new belt and make sure it's properly tensioned.

Oh, and what do you mean about abusing the gas pedal within the first 30 seconds? PLEASE tell us you're not racing the engine before it's warmed up!

Peryn · 09-12-2003, 09:24 AM

Your mechanic is pretty dumb. I mean really, a belt will cost a few bucks. MUCH cheaper than an alternator. And after seeing you that often hes just says "uhh.....i dunno" and STILL hasn't replaced the belt? You need to tell him you want a new belt on there. Mark your old one someplace inconspicuous (sp?) so you know for sure that he did. See if that helps.

First thing you should do for a belt problem is retension it and then replace it. They are so cheap usually...

Sion · 09-13-2003, 08:27 AM

ok, first off, is there just one belt, or multiple? if one, that eliminates the next step, which is to determine which belt is doing the squealing. this is most easily accomplished using either a spray-on "stop squeal" product or, as mentioned, a bar of soap. just apply the product to each belt in turn until you determine, but the sudden lack of squeal, which is the culprit. once you know which belt it is, then it comes down to determining which of the accessories on that belt (ie power steering, alternator, a/c, smog pump, water pump, etc) on that belt is causing the problem. you see, given the fact that you have had the belt retensioned several times and the problem still recurs, then the answer is one of two things. either:

a) the belt keeps coming loose. if the vehicle has an automatic, spring loaded tensioner (which I doubt, considering what you've said) then I would look at the tensioner. if not, then it is tensioned by the mechanic via one of the accessories being on a pivot (usually the alternator, but not always). in any case, unless your mechanic is incapable of properly tightening a damned bolt, then Id say the belt is not so much coming loose as it is:

b) the bearings in one of the accessory pulleys are going bad. no matter how tight the belt is, IF the bearings in one of the pulleys are beginning to fail (not unlikely given the age of the vehicle) then there will be resistance to the spinning action that the belt provides. hence, the belt will slip and squeal until the pulley reaches the same speed that the belt is travelling. in this situation, it will be necessary to determine which of these pulleys has bad bearings and replace either the pulley (which will come with the bearing) if that is possible, or if not, then the entire accessory part. since you have had the alternator replaced, then we can assume thats not it, since the problem has returned. next two most likely culprits are the airconditioning compressor (if the car has a/c) and the water pump. a/c compressors are notorious causes of belt squeal, because not only do they have bearings which can go bad, but also the pulley itself is part of a clutch mechanism that can fail. here is a quick test to try. start the car and let it run with the a/c off until the belt squeal goes away and the car is warmed up (say 5 mins). now, without touching the gas pedal, put the a/c on. does the belt squeal for a second or 3? if so, you have found your culprit.

if that doesnt pinpoint the bad pulley/bearing, then the only other choice is to remove the belt and hand turn each and every pulley (idler/tensioner pulleys too) that the belt rides on, trying to find the one(s) that dont turn nice and smooth.

absolute worst case scenario: you've tired all of the above and nothing has revealed itself. live with it until such time as the belt WONT STOP squealing no matter what. now you should be able to determine which pulley wont spin freely, as it likely wont spin at all.

btw: find a new mechanic. this one doesnt know his ass from a hole in the ground.

note: contrary to popular belief, if IS possible to overtighten a belt. that is why they have specifications for belt tension (whether V-belt or serpentine, there IS a specification for tension). if you make a belt too tight, it WILL put excess stress on the bearings in ALL the pulleys on that system (even the crank pulley) causing any or all of them to wear out prematurely.

simple rules of thumb for the backyard mechanic who doesnt own a belt tension measuring device:

for V-belts: if you can grab the belt and rotate it 180 degrees, it is TOO LOOSE. you should be able to rotate it about 90 degrees. if not, it is too tight.

for serpentine belts: if you put your thumb on the belt in the middle of a section that is at least 8 inches from pulley to pulley, you should be able to push it down no more than 1/2 inch. if you can push it down more, its too loose. if you cant push it down that much, its too tight.

Sion · 09-13-2003, 08:29 AM

oh, and I almost forgot: once you determine what exactly is the problem and correct it, go ahead and replace the belt while you are at it. all that slipping it has been doing is NOT good for it. spend the extra $10 or $20 dollars and replace it WHILE YOU HAVE IT OFF ANYWAY.

mystic511 · 09-13-2003, 06:55 PM

How many miles you have on your engine? On my eclipse, at 60k miles, the tensioner pulley and some other parts must be replaced mandatorily just due to natural wear. You may have something similar that you are unaware of. Consult your owner's manual or roll into a mazda dealer and ask for the XX,000 mile service checklist.

Your mechanic may not be wrong that the belt is perfectly fine, but I agree that you should get a new mechanic if he's not taking the time to find out exactly what's wrong. I have to raise my eyebrow on his decision to change out the alternator... sounds like he's milkin you.

A perfectly installed belt will not squeek. It should not need dressing or anything to dampen squeeking. If the belt is fine, something else along it's rotation is making the squeeking. Can't really say for sure what it is, but regardless, opt to change to a new belt when it's identified and fixed. You don't know what the current belt has been through, if it's been stretched, beat up, etc.

WarWagon · 09-14-2003, 04:08 PM

If its been squealing that much for that long, then its probably long glazed over by now. Slap on a new one, and take some coarse grit sandpaper to your pulleys if you get the chance.

starbum · 09-14-2003, 04:50 PM

Thanks for all your help guys. Actually its more than one mechanic thats doing the work, but I'll concider moving elsewhere anyways. Whenever they tighten the belt its all fine. I drive about 250 miles every weekend, so after say...750 miles it begins to quietly sqeak, then get louder and louder. I take it to them and they say its loose again......i've requested to them multiple times to just replace the damn thing but they dont seem to want to do that. I guess i'll have to force them to or go somewhere else. bastards.

mystic: approaching 80k

sakran: was only joking. abusing as in, just accelerating. Im not a speed demon....hell, its only a 4cyl...lol.

PDOUBLEOP · 09-21-2004, 09:50 AM

On the same subject...I just replaced my alternator and serpentine belt because the old one was starting to split in places. I wasn't having any squeaking problems. Now, when I turn on too many accessories it squeals like hell til I turn something off. What gives? Bad new belt? Improper alignment?(it was kinda dark and hard to see when I replaced it)

Sion · 09-21-2004, 11:53 AM

Pdoubleop: the belt is likely too loose. a squeak/squeal from a belt and pulley system means one of two things: belt too loose or a bearing failing in one of the pulleys. In your case, since there was no noise before, its logical to presume that the source of the noise is the repair work that you did (sorry, I dont mean to insult here, just pointing out the logic). Now, what happens when you turn on lots of accessories that consume electricity (dont they all?) is that the alternator must put out more juice to meet the demand. Because Im not an electrician, I cant explain the process inside the alternator very well, but the result of the increased demand for electricity is that the alternator gets harder to turn. So your belt, which was tensioned ok for low electrical demand is no longer tight enough for the high demand.

Check the belt tension and see that meets specification. Your noise problem should disappear once it does.

compression · 09-21-2004, 12:24 PM

Dont forget that the crank pulley could be worn. Yes the rubber does wear down the metal over a long period of time. But 80k is hardly a long period of time....But sounds like what ever is tensioning the belt is not staying put.
Time for a new car!

09-12-2003, 04:55 AM	#1 (permalink)
starbum Tilted	Belt sqeaks like MAD The belt in my car (mazda 94 MX3) sqeaks alot. And its only when I start the car and for the first 30 seconds of my drive, depending on how much I abuse the gas pedal. Gets louder when I accelerate, then dissapears. I've taken it to the shop, they've tightened the damn thing 7 times now. It works for about a week or so, then it sqeaks again. I took it back and they replaced the alternator. That worked for 2 weeks, then it sqeaked again. wtf is going on? They refuse to replace the belt itself because they say its perfect.... they say that it somehow loosens itself and that causes the sqeaking. What could be causing the belt to sqeak? They also noted that the mounting bolts for the engine might be loose or broken. FUN.

09-12-2003, 07:11 AM	#2 (permalink)
weasel2112 Upright Location: Lost in space	Go to the autoparts store and either replace the belt or get some stop squeak. Some belts new or old will squeak when you they are cold. __________________ My Bad Ass Hummer

09-12-2003, 07:12 AM	#3 (permalink)
Scorps Lost!! Location: Kingston, Ontario	All you need is a new belt __________________ A.K.A. PainTrain

09-12-2003, 09:24 AM	#6 (permalink)
Peryn Junkie Location: San Diego, CA.	Your mechanic is pretty dumb. I mean really, a belt will cost a few bucks. MUCH cheaper than an alternator. And after seeing you that often hes just says "uhh.....i dunno" and STILL hasn't replaced the belt? You need to tell him you want a new belt on there. Mark your old one someplace inconspicuous (sp?) so you know for sure that he did. See if that helps. First thing you should do for a belt problem is retension it and then replace it. They are so cheap usually... __________________ Dont cry kid, It's not your fault you suck.

09-13-2003, 08:27 AM	#7 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	ok, first off, is there just one belt, or multiple? if one, that eliminates the next step, which is to determine which belt is doing the squealing. this is most easily accomplished using either a spray-on "stop squeal" product or, as mentioned, a bar of soap. just apply the product to each belt in turn until you determine, but the sudden lack of squeal, which is the culprit. once you know which belt it is, then it comes down to determining which of the accessories on that belt (ie power steering, alternator, a/c, smog pump, water pump, etc) on that belt is causing the problem. you see, given the fact that you have had the belt retensioned several times and the problem still recurs, then the answer is one of two things. either: a) the belt keeps coming loose. if the vehicle has an automatic, spring loaded tensioner (which I doubt, considering what you've said) then I would look at the tensioner. if not, then it is tensioned by the mechanic via one of the accessories being on a pivot (usually the alternator, but not always). in any case, unless your mechanic is incapable of properly tightening a damned bolt, then Id say the belt is not so much coming loose as it is: b) the bearings in one of the accessory pulleys are going bad. no matter how tight the belt is, IF the bearings in one of the pulleys are beginning to fail (not unlikely given the age of the vehicle) then there will be resistance to the spinning action that the belt provides. hence, the belt will slip and squeal until the pulley reaches the same speed that the belt is travelling. in this situation, it will be necessary to determine which of these pulleys has bad bearings and replace either the pulley (which will come with the bearing) if that is possible, or if not, then the entire accessory part. since you have had the alternator replaced, then we can assume thats not it, since the problem has returned. next two most likely culprits are the airconditioning compressor (if the car has a/c) and the water pump. a/c compressors are notorious causes of belt squeal, because not only do they have bearings which can go bad, but also the pulley itself is part of a clutch mechanism that can fail. here is a quick test to try. start the car and let it run with the a/c off until the belt squeal goes away and the car is warmed up (say 5 mins). now, without touching the gas pedal, put the a/c on. does the belt squeal for a second or 3? if so, you have found your culprit. if that doesnt pinpoint the bad pulley/bearing, then the only other choice is to remove the belt and hand turn each and every pulley (idler/tensioner pulleys too) that the belt rides on, trying to find the one(s) that dont turn nice and smooth. absolute worst case scenario: you've tired all of the above and nothing has revealed itself. live with it until such time as the belt WONT STOP squealing no matter what. now you should be able to determine which pulley wont spin freely, as it likely wont spin at all. btw: find a new mechanic. this one doesnt know his ass from a hole in the ground. note: contrary to popular belief, if IS possible to overtighten a belt. that is why they have specifications for belt tension (whether V-belt or serpentine, there IS a specification for tension). if you make a belt too tight, it WILL put excess stress on the bearings in ALL the pulleys on that system (even the crank pulley) causing any or all of them to wear out prematurely. simple rules of thumb for the backyard mechanic who doesnt own a belt tension measuring device: for V-belts: if you can grab the belt and rotate it 180 degrees, it is TOO LOOSE. you should be able to rotate it about 90 degrees. if not, it is too tight. for serpentine belts: if you put your thumb on the belt in the middle of a section that is at least 8 inches from pulley to pulley, you should be able to push it down no more than 1/2 inch. if you can push it down more, its too loose. if you cant push it down that much, its too tight. __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...

09-12-2003, 08:06 AM	#4 (permalink)
dailyjo2003 Tilted	New belt -or - take a bar of soap and rub it on the inside of the belt - that will stop the squeaking

09-12-2003, 08:43 AM	#5 (permalink)
shakran Tone.	And cause the belt to slip, and potentially break the belt down. Not a good idea. Just get a new belt and make sure it's properly tensioned. Oh, and what do you mean about abusing the gas pedal within the first 30 seconds? PLEASE tell us you're not racing the engine before it's warmed up!

09-13-2003, 08:29 AM	#8 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	oh, and I almost forgot: once you determine what exactly is the problem and correct it, go ahead and replace the belt while you are at it. all that slipping it has been doing is NOT good for it. spend the extra $10 or $20 dollars and replace it WHILE YOU HAVE IT OFF ANYWAY. __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...

09-13-2003, 06:55 PM	#9 (permalink)
mystic511 Tilted	How many miles you have on your engine? On my eclipse, at 60k miles, the tensioner pulley and some other parts must be replaced mandatorily just due to natural wear. You may have something similar that you are unaware of. Consult your owner's manual or roll into a mazda dealer and ask for the XX,000 mile service checklist. Your mechanic may not be wrong that the belt is perfectly fine, but I agree that you should get a new mechanic if he's not taking the time to find out exactly what's wrong. I have to raise my eyebrow on his decision to change out the alternator... sounds like he's milkin you. A perfectly installed belt will not squeek. It should not need dressing or anything to dampen squeeking. If the belt is fine, something else along it's rotation is making the squeeking. Can't really say for sure what it is, but regardless, opt to change to a new belt when it's identified and fixed. You don't know what the current belt has been through, if it's been stretched, beat up, etc. __________________ One day, I will become Virtually Infamous.

09-14-2003, 04:08 PM	#10 (permalink)
WarWagon Loser	If its been squealing that much for that long, then its probably long glazed over by now. Slap on a new one, and take some coarse grit sandpaper to your pulleys if you get the chance.

09-14-2003, 04:50 PM	#11 (permalink)
starbum Tilted	Thanks for all your help guys. Actually its more than one mechanic thats doing the work, but I'll concider moving elsewhere anyways. Whenever they tighten the belt its all fine. I drive about 250 miles every weekend, so after say...750 miles it begins to quietly sqeak, then get louder and louder. I take it to them and they say its loose again......i've requested to them multiple times to just replace the damn thing but they dont seem to want to do that. I guess i'll have to force them to or go somewhere else. bastards. mystic: approaching 80k sakran: was only joking. abusing as in, just accelerating. Im not a speed demon....hell, its only a 4cyl...lol.

09-21-2004, 09:50 AM	#12 (permalink)
PDOUBLEOP Insane	On the same subject...I just replaced my alternator and serpentine belt because the old one was starting to split in places. I wasn't having any squeaking problems. Now, when I turn on too many accessories it squeals like hell til I turn something off. What gives? Bad new belt? Improper alignment?(it was kinda dark and hard to see when I replaced it) __________________ ef you-you effing ef

09-21-2004, 11:53 AM	#13 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	Pdoubleop: the belt is likely too loose. a squeak/squeal from a belt and pulley system means one of two things: belt too loose or a bearing failing in one of the pulleys. In your case, since there was no noise before, its logical to presume that the source of the noise is the repair work that you did (sorry, I dont mean to insult here, just pointing out the logic). Now, what happens when you turn on lots of accessories that consume electricity (dont they all?) is that the alternator must put out more juice to meet the demand. Because Im not an electrician, I cant explain the process inside the alternator very well, but the result of the increased demand for electricity is that the alternator gets harder to turn. So your belt, which was tensioned ok for low electrical demand is no longer tight enough for the high demand. Check the belt tension and see that meets specification. Your noise problem should disappear once it does. __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...

09-21-2004, 12:24 PM	#14 (permalink)
compression Upright	Dont forget that the crank pulley could be worn. Yes the rubber does wear down the metal over a long period of time. But 80k is hardly a long period of time....But sounds like what ever is tensioning the belt is not staying put. Time for a new car!