Car question: Squeaking alternator belt

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Car question: Squeaking alternator belt

Car: 2002 Celica VVTi 140

Problem: The alternator belt is squeaking.

Question: What causes this? What do I need to do to fix it? Is a belt change (PITA to get to) all that's needed?

one can get "belt dressing" sprays from car shops..otherwise a blast of WD40 may do the trick asumeing its adjusted right and everything.

Yep, a light spray of WD40 does the trick. If it doesnt then it might not be the belt, it could be be of the bearings in the alternator. Does it onoy do it on start up? If you turn the lights on for a five mins then start the car is the noise worse?

WD40 will shut it up for about 20 mins..then the WD40 dries out and the squeek will return, New Belt proably

Deleted 287 (not verified)

defo needs replacement

Is the belt loose?

You just need to tighten it - probably. You should be able to losen the alternator bolts then use a lever to get the belt tight then re-tighten the bolts while still holding the alternator. It'll probably be hard to get to as its a new car.Or it could be that the adjustment is not on the alternator, but maybe the a/c pump or suchlike if they are driven on the same belt.

Tomcat wrote

Interesting cos my diesel Tranny does this when it's cold. Generally when the alternator goes on load. The belt looks in OK condition and isn't loose, so far I've lived with it as it stops after about 5 minutes but the neighbours cat ain't happy

My diesel Tranny does it also on startup, just for a few seconds though.I intend to tighten it up as it's not a hard job but just not got round to it yet, never occured to me about it possibly being due to waterpump seals being damaged so I will check that out as well.

just buy a new one......job done !

You can buy a specialist "Belt Dressing" spray from agricultural outlet suppliers, its used on belt driven farm machinery, but we used it quite a lot in the plant industry & garage equipment for slipping or squealing belts and it works a treat.

A belt shouldn't make that noise, Full Stop! It needs to be tightened or if cracked it needs replacing. There is no point spending money on sprays as it doesn't stop the problem it just covers it for a while.Its slipping as the alternator is working harder to charge the battery due to lights heated screen/mirrors and heater being on more due to the time of the year.Tightening it usually is a matter of undoing a douple of bolts moving the alt, then re-tightening the bolts again. It needs doing as every time the belt slips its being worn out and eventually will shred itself and leave you stranded.

Can be caused by the contact patch (the sides) glazing over due to wear and tear - same has brake pads do when they've been over-heated.Liquid soap works better than WD40 (oil based lubricant), but a new belt would cure it completely.

Since I mentiones this I have noticed that mine is getting through a bit of water Still it's getting serviced next week and a new cambelt so I think it's best to get the waterpump seal checked out then I can't see any leaks but the waters going somewhere and I have checked the oil and theres no water in it, also I have checked the water and theres no oil in it so it looks like the head gaskets OK.To tighten the fanbelt isn't exactly rocket science on mine as I just have to loosen one bolt then take up the tension (bit like tightening a bike chain) with another bolt, then just do the first one up again.

talcum powder..........works for me.mustard powder for rad leaks.and get more air over ballaugh TC, jump further than that on mad sunday.....past the copper

U don't need a new belt unless there is severe cracks to the belt or if the it lost its elasticity. So check that first. Then the next solution would be to pinpoint the exact spot. Could be something that sounds like the belt but isn't. Get a flexible hose and put it to your ear. I replaced both power steering and alternator belt because they were off from another repair and they needed it. Worked well for a week or two. Starting squeaking. Tightented the alternator belt again and the problem went away for months. Now I have a very low squeak just when I start it. Stops within a second. So time to tighten again. It is very cold over here now and I think that has a lot to do with it. I think the atoms form closer making the belt lose flexability. Works great when the car is warm. And don't spray wd40 on it like some suggest. That is a temporary fix. Like 5 minute temporary fix. unless the pulley has rust on it and making the belt slip. I have never tried the soap idea but that still seems to me as masking the problem unless the belt is tightened perfect and it is just rubbing on something.

I installed a brand new bosch serpentine belt for the alternator.crankshaft.   It squeaks relly loudly.  All pulleys have no bearing issue.  The alignment of the pulleys are good.  Any suggestions?  Pierre

The simple answer is that the belt isn't tensioned correctly. What car is it? Do you have a repair / service manual for it? If not you can estimate the correct tension but it helps to know what the car & belt set up is. Does is just go from crank pulley to alternator pulley or are there others on the same belt? What's the distance from the crank pulley to the alternator pulley?

This is a common problem ( Technician, 30 years experience). When a new belt tensioned correctly still squeaks, especially on start up There can be 2 problems...

1. The sides of the pulleys are worn and the belt is bottoming out, going to deep into the pulley, thus loosing grip on the v sides.

2. Squeak on start up can be exasperated if there is a drain on the battery while the engine is stopped, lights on, radio on whatever. Thus puts a heavier load on the belt at start up as the alternater is working harder

you guys are amazing

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