A/C belt squeals when turning on and off A/C or accelerating

[ebibb]

 I have a 1995 Subaru Legacy L s/w and replaced the A/C belt last summer after replacing the power steering pump.  Ever since then, the A/C belt has squealed either when turning on the A/C or driving after it's on.  It usually only lasts for 10 - 20 seconds, although there are times when it just won't stop and I have to go without A/C for a little while.  As the squeal goes away, it sounds like a belt noise fading out, however, I know it could be something else entirely. The belt is tight so it's not a loose belt thing, but I don't know what else it could be.  Any ideas? 

[luko]

Just how tight is the belt though? like how much play is in it? There is also a torque spec for it as well 

[okamikai]

I've seen this before, sometimes it doesn't matter if you replace the belt it may squeal a little, but not for that long. Another thing you should look at is the A/C pulley, when the compressor bearings wear out they will slow down the pulley's rotation, but since the engine will not stop for that it will force the belt to slip on the pulley's surface. Take the belt off and check if that stops the noise, if it does you found your problem. Hope this can be of help.

[john in KY]

Belt needs to be replaced, now glazed,  and adjusted correctly. 

[ebibb]

Luko, Okamakai, and john in KY,

 

The belt is pretty tight, maybe 1/2" total play.  I didn't check for torque speck though.  I guess I'm still old school.  I'll try replacing the belt first and while I have it off I'll see if the A/C unit still squeals. 

 

Thanks for all of the suggestions! 

 

ebibb

[Downbound]

Had exactly the same whine in my 2001 forester. Turned out to be the AC  idler pully, also needed to repair the tensioner mount.

[1 Lucky Texan]

they didn't sell you one of those new stretch-type belts by mistake did they?

[porcupine73]

Sometimes the a/c compressor clutch will squeal for a moment when it kicks in but usually I don't think it would be a continuous squealing.

[nipper]

Belt is slipping, check the idler pully assembly. not unusual for them to go bad when they are this old.

[ebibb]

Sorry to have been offline for so long.  Sometimes life gets in the way.  I did not replace the belt, just checked the tightness as it started to get into the colder part of the season without need of the A/C.  Okay, here are a few more symptoms with the belt noise problems.  Every day when I crank the car the belt squeals automatically.  The only way to stop the noise without waking up the neighbors is to put the vehicle in gear which stops the noise.  When driving with the air on, it squeals with regularity.  It will go away by releasing the gas pedal or, at times, by giving more gas.  Now, here's something odd.  When sitting in traffic or anyplace with the engine idling, it does not squeal at all, although, when taking off again, the squeal may return.  I hope this will narrow down the problem a little.  I don't want to overspend or buy the wrong parts to repair the problem. Any ideas?

 

Thanks,

 

ebibb

[1 Lucky Texan]

I think you should inspect the crank pulley for separation.

[Fairtax4me]

Belt is loose. Possibly the bearing in the tensioner is going bad.

 

If the belt has been squealing for some time, its probably glazed now and will need to be replaced.

[1 Lucky Texan]

if it does it reliably after you start and idle in the mornings, you could 'probably' prove it's the belt again by spraying something like this on it;