AC Squeel? Alternator squeel?
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
AC Squeel? Alternator squeel?
I think my AC compressor is starting to squeel. Sometimes when the engine is cold I get a squeek that changes speed with engine speed. I noticed that noise changes if I turn on the AC and the sound comes from that side of the engine compartment.
Is it possible that the Alternator can squeek and the sound is changing because of the increased load of the AC?
BTW...the water pump was changed last summer.
Is it possible that the Alternator can squeek and the sound is changing because of the increased load of the AC?
BTW...the water pump was changed last summer.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
how old and how many miles on belt
pull it out and examine for cracking and glazing
the 4L serpentine drives accessories on both inside and outside face, the 3L?
glazed belt will make noise.
grease on belt/pulleys will cause slippage noise
damaged bent pulley will cause noise
dry worn bearing in alternator, compressor or water pump will cause noise.
there should be no noise from the increased AC fan electrical load on the alternator unless there is a component failure
i'd drop the belt off and spin each accessory for smoothness of bearings and component.
pull it out and examine for cracking and glazing
the 4L serpentine drives accessories on both inside and outside face, the 3L?
glazed belt will make noise.
grease on belt/pulleys will cause slippage noise
damaged bent pulley will cause noise
dry worn bearing in alternator, compressor or water pump will cause noise.
there should be no noise from the increased AC fan electrical load on the alternator unless there is a component failure
i'd drop the belt off and spin each accessory for smoothness of bearings and component.
Elder User
Joined: Apr 2005
Posts: 882
Likes: 0
From: Wichita
I had a similar problem when I changed my p/s pump. The serpentine belt was 7 years old and it just wouldn't tolerate the fluid spilled on it. I replaced the belt and all is well.
To determine if your belt is worn out, spray a little silicone or WD40 on it. If it goes quiet, it's likely that it is bad. If it doesn't, it may be a pulley.
To determine if your belt is worn out, spray a little silicone or WD40 on it. If it goes quiet, it's likely that it is bad. If it doesn't, it may be a pulley.
Thread Starter
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Mountain Pass
Joined: Jun 2003
Posts: 208
Likes: 3
From: Norfolk VA
The belt is a couple of years years old with maybe 10K miles on it. I don't see any cracking or glazing on the belt.
This van is a 3L and the sound is clearly on the alternator and AC compressor side.
wouldn't spraying WD-40 on the belt cause more squeeling and slippage?
Thanks
Doug
This van is a 3L and the sound is clearly on the alternator and AC compressor side.
wouldn't spraying WD-40 on the belt cause more squeeling and slippage?
Thanks
Doug
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
try some spray on belt dressing to stop any slippage
use to have to use it on my 4L when i used to tow with it in extreme heat.
slippage can also be caused by an old weak tensioner pulley unit
use to have to use it on my 4L when i used to tow with it in extreme heat.
slippage can also be caused by an old weak tensioner pulley unit
Senior User
Joined: Nov 2001
Posts: 319
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From: Sacramento
belt squeal
On my '96 4.0, the squealing began with a new aftermarket belt. Changed it, no squeal. Of course, that was after lots of worrying about alternator bearings, AC clutches, et al. Put a name brand belt on, and all was quiet, still is.
Elder User
Joined: Apr 2005
Posts: 882
Likes: 0
From: Wichita
I'm having that problem right now. I put a new Dayco belt on and it chirps. Put my old Motorcraft belt on and it doesn't. I found this out after I already replaced the tensioner.
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Mountain Pass
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Elder User
Joined: Apr 2005
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From: Wichita
Sure. Just like tires, as they warm up they build up friction. It's not the case in my situation but it could happen.
Elder User
Joined: Apr 2004
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I hate to differ but I don't think the advice about spraying the belt is good. Years ago when we ran the wide vee belts and the tension wasn't high (3/8 of an inch deflection) that stuff was used to give them a bit of traction, now all it does is lubricates the slipping surface. You can tell if it is the ac or the alternator by shutting the ac off as well as the defroster which free wheels the ac clutch. If the squeal isn't there then you know the ac clutch isn't slipping causing the noise. Now if the belt isn't tensioned properly and the battery is not quite up to snuff and the alternator has to charge at a higher rate until it is brought back up and if the belt is it will squeal. My 2 cents Kotzy
Elder User
Joined: Dec 2006
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From: Kitchener,Ontario,Canada
I think my AC compressor is starting to squeel. Sometimes when the engine is cold I get a squeek that changes speed with engine speed. I noticed that noise changes if I turn on the AC and the sound comes from that side of the engine compartment.
Is it possible that the Alternator can squeek and the sound is changing because of the increased load of the AC?
BTW...the water pump was changed last summer.
Is it possible that the Alternator can squeek and the sound is changing because of the increased load of the AC?
BTW...the water pump was changed last summer.