Belt squeal

J

jukon

Member
:
02 MP5
Hi all,

So my belt squeals occasionally. Only after startup and more often in damp weather. I've read on here that it's likely my alternator belt and I check it and it does seem to twist more than halfway. I tried locating the bolts to tighten it but I'm having a problem with the one at the bottom. The top is pretty straight forward and I've tried getting the bottom one from below but I think I may have the wrong bolt? The bolt that I think it is, I can't even find a socket to fit. Nothing fits, it's either too big or too small. Can you guys please provide a bit more detail on this bottom bolt I need to loosen?

thanks.
 
I never bothered loosening the bottom bolt. I just loosened the top bolt then cranked the adjuster. The bottom bolt just pivoted a bit.
 
Yeah, my belt has a pretty bad squeal too sometimes. Usually when starting up, but it sometimes has a fit when I'm driving slow. Goes away once I rev to 2200+ rpm.
 
I have the same issue too, but I just had my alternator replaced a few months ago and brought it back to them a few weeks later to have the belt retensioned. So I wanna say mine's the AC/power steering belt. Hopefully that one isn't too different so I can do it myself. Getting in there is a pain though. My belt's been making more noise lately with cold starts and from a rolling stop, but once I rev past about 3500 it usually goes away.
 
Last edited:
AC/Power steering belt one is simple. Can do that one all through the top. But if it gets worse by kicking on electronics a/c, rear window defroster, etc right at startup then it is most likely the alternator belt.
It's just that bolt on the bottom that's relatively far back for the alternator that makes that one a pain.
 
Hmm...maybe it is my alternator belt then. Having the fan on usually gets it to act up. I was thinkin that might just be related to the AC system though, even though it's sometimes when I have the heat on.
 
You need new belts. I paid a little over $20 for both of them
yea you can try adjusting the tension on them, but why? if its squeaking it means its slipping. if its been slipping, its been rubbing against the pulley, its done regardless.
plus you are going to be messing with the tension anyways, chances are the belts are going to fall righ off anyways and you will have to put them back on.
when i removed the engine, i removed the alternator and power steering pump. but the belts fell right off when i loosened the long screw in/out bolts up top. (tensioners).
the bottom bolts are to actually remove the alternator/p.s. pump.
 
I am having this exact problem. It is getting cold and wet lately, and when I first start my car it squeals like its a belt for the first 30 seconds or so. Then after that it tends to stop. It will start occasionally if I'm stopped at a red light, or waiting for coffee at McDonalds. I think its doing it when the AC kicks on, since I have my defrosters on. While I'm sitting there with the brakes pressed for a minute or so, the engine will rev up slightly (which I'm guessing is the AC kicking on) and that seems to be when the squeaking starts up again.

I just had the alternator and belt replaced, it seems pretty tight. I also just replaced the serpentine belt, thinking at first it was that. Its also tight now. Last night I just put in new power steering fluid, the kind that says it will help prevent squeaks. No change. This is all why I think the people mentioning the AC belt is the problem. My problem - where is this belt? Does anyone have a picture or instruction I can use to help me weed this out? I'm pretty much learning how to fix the car as I go :) This site has been very helpful!
 
You can tighten or replace the belts all you want, it's not going to fix the problem. I've replaced the belts, I've tightened the belts, and I've replaced the alternator. It just doesn't stop.It's just a poor design (On this car?! Go figure.).

And it's probably the alternator belt, not the AC belt. I bet it squeals every time you turn something electrical on. Over tension will wear every bearing that belt runs arounds. I'd rather it squealed.
 
I have found that only OEM and Gates belts tend to not squeal on Mazdas. Other brands tend to be more prone to squealing in my experience.
 
I have had good luck with Dayco belts, had them about 3 years and never heard a noise. The belts squeal due to improper tensioning, not so much the belt itself.
 
Maroon said:
You can tighten or replace the belts all you want, it's not going to fix the problem. I've replaced the belts, I've tightened the belts, and I've replaced the alternator. It just doesn't stop.It's just a poor design (On this car?! Go figure.).

And it's probably the alternator belt, not the AC belt. I bet it squeals every time you turn something electrical on. Over tension will wear every bearing that belt runs arounds. I'd rather it squealed.
Click to expand...

Unless your car came off the lot with the belt squeling, its not the "design".
.... i REALLY hope you guys are cleaning the pulleys before placing the new belts on. It would be a shame if you went through the procedure only to throw new belts ontop of all the dirt and rotted old rubber dust. the dust would work as a dry lube, and that belt will spin even if its new.
 
mp5build2013 said:
Unless your car came off the lot with the belt squeling, its not the "design".
.... i REALLY hope you guys are cleaning the pulleys before placing the new belts on. It would be a shame if you went through the procedure only to throw new belts ontop of all the dirt and rotted old rubber dust. the dust would work as a dry lube, and that belt will spin even if its new.
Click to expand...

The life and durability of any part are the responsibilities of design. Those are 2 things that every OEM - well, except Mazda - tests for. Do a search, and you'll find that this was a common problem on low mileage Proteges. This is a design problem.

Cleaning the pulleys? There's no dust or dirt. And nobody cleans the pulleys of any other vehicle. Maybe you could make an argument that they're "too polished", but again, that's not a problem on any other vehicle.
 
It took a few tries for me to dial my new gatorbacks in properly but no more squeal coming out of mine even now with temps in the 30s.
 
Hmmm well I doubt its a design problem since it only started doing this recently. I'll look for the A/C belt this weekend. I'll also check the alternator belt to make sure nothing looks weird. It seemed tight last weekend, and we definitely tightened the serpentine belt up, there's no way that's the problem. I'll tinker some more with it and let you all know if I can seem to find the source of this squeaking. Thanks!
 
I vote for a design problem as well. I have tried Goodyear, Dayco & Gates belts as well as taking a soaking once at the dealer for Mazda belts. Nothing, and I mean NOTHING, not tensioning, not pulley cleaning, not new belts keeps my Mazda belt from squealing at random times.
 
Nope. Not design.
Proper installation of Daycos do not squeal. This includes re-torqueing the belts after a 50 miles~ish and they have seated/stretched.
Once they have been slipping quite a bit - the belt is glazed and will not stop squealing no matter how much tension....
Lastly - too tight and you will stress the bearings and make THEM squeal... :(

I suggest you go back and re-read slipping belt posts. There is always a fix (usually pertaining to what i said...).
 
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