Engine Squealing

[ab_slack]

87 BII with 2.9L. At the title says there is a squealing sound coming from the engine. It is quite loud. My initial suspicion was that a belt was squealing, but it has none of the typical non-linearity as rpm is increased where the squeal will change or go away. So I am thinking maybe a bearing in the alternator, water pump, power steering pump, AC compressor.

I am trying to resolve this today if possible. Anyone have any good tips to help isolate what it might be or other suggestions?

The belts were all replaced about a year ago and at this point have about 10K miles on them. That doesn't seem like much and they look in good shape.

I really can't pinpoint a sound location, but I can't get a good sense really.

The only maybe sort of clue I have right now is that in the belt going to the alternator, the part that comes off the top of the pulley seems to have a bit of bounce in it when it is rotating. It doesn't seem unusually loose and I with engine off I can't turn the alternator. I am wondering if maybe the problem is the alternator and the bounce is from how difficult it is to turn.

I don't know how normal some bounce is, but it is the only one doing that.

So right now I am loosening the alternator and seeing how freely it spins without the belt. If it is bad, I'll know where to go.

If that is fine however, not sure where to go next so I am hoping for some other tricks or ideas when I check back.

 

[RonD]

First remove the belt from the crank and start the engine.
It is OK to run a cold engine a few minutes without water pump.
Battery light will come on, as alternator is not turning.

If squeal is gone then you will know one of accessories pulleys is bad, not something else in the engine.

Spin each, don't forget tensioner pulley if it has one.

 

[ab_slack]

It was squealing before I started.

Loosened the alternator to get it's belt free. Alternator spins freely without the belt. Giving it a good spin it continues for another turn on it's own. Didn't seem like much resistance to turning. The only thing that seemed like possibly a problem, is when turning I faintly heard like some small clicks.

I taped that belt back so it couldn't get tangled (didn't want to go pulling them all yet) and started it. No squealing, all sounded smooth.. Suggests the alternator.

But alternator seemed fine.

Put the belt back on. Approximately the same tension, perhaps a little looser. No noise again.

Moved the car to a different spot to check oil and coolant. After doing that, when I started it again, noise was back.

I tried pouring some water on the belts thinking if it changes the sound that indicate slippage of that belt. No effect.

I tried spraying a bit of WD40 on the alternator front bearing under the pulley and thru the vent opening on the shaft inside. When I started it made noise unchanged. Within a minute the noise started to fade. Not sure if associated with the WD40 or if it was just that things were warming up a bit. It has made noise when hot but varies.

When it started to fade out, I would hear it come and go faintly, never entirely going.

While the alternator seemed to spin fine, could it be sticking when under the tension from the belt?

The squeal is more of a 2 or 3 times a second screech.

I am going to try and get some more tension on the alternator belt see if that helps or hurts the situation. Not exactly how to lever it to get more tension on the belt since it doesn't have a tension adjustment mechanism that I can find.

 

[RonD]

Reads like the alternator has a bad bearing or brushes, coming and going reads like brushes.

If you have a "V" belt then the alternator will have a slotted adjustment bracket, lossen Pivot bolt(under alternator) then loosen adjustment bolt, pull alternator tight against belt sometimes you can use a longer wrench(stick) as a lever to hold belt tension while you tighten the adjustment bolt.
Then tighten Pivot bolt.

You want less then a 1/2" of deflection on the longest open part of the belt, so it you push on the belt with your finger it should move less than 1/2"

 

[ab_slack]

Thanks Ron, that matches another opinion I got this evening, so I might just replace it. I was at the auto parts place for other stuff, but apparently there are several different possibilities.

Understand how to adjust. It is a V belt as you mentioned. I just just don't have the strength to pull with enough force even with a screwdriver in the one place I can pry. I probably have closer to 1" to 1 1/2 inch worth of belt deflection.

 

[RonD]

You can often use the adjustment slot to pry against the alternator, so put 1 or2 screwdrivers in the slot and pry against the bolt or holder

 

[KBlaze]

I use an adjustable wrench or regular wrench on the square part of alternator where bolt is and pull tight.

 

[wildbill23c]

^^This works very well.

 

[ab_slack]

Well, I swapped out the alternator, and...it still made noise

I thought I had it in the bag, especially upon checking the alternator again and finding it made more noise when turning than my first check, but apparently not.

I did have to transfer the pulley from the old alternator. Could the pulley be the cause? The new alternator had a pulley for a flat belt instead of a V belt. I ran it with belt looser and tighter on the alternator (once I got a good method) and made no difference. I didn't try pulling the belt off the alternator completely again.

I have eliminated the compressor as a cause as well, since it didn't work I just left that belt off.

I am now suspicious that maybe the fan clutch is the cause? Every B2 I have had has had the fan clutch go bad, but I don't recall any sort of squealing. Instead it just wouldn't release at high RPM making lots of fan noise and loading the engine. This particular fan clutch was replaced about 15 months ago (abt 10K miles) so I am not impressed if the new one is bad.

Nice Idea KBlaze, I'll keep it in mind. I could not use it here tho The throttle body was in the way. If I had one of those old style 90 deg type wrenches (the ones used with square bolts) I probably could get a good grab on it. tho. Thank you.

 

[Mark_88]

I replaced an alternator once for the same reason...squealing...the new one squealed louder than the old one...so I put the old one back on, used a pry bar under the alternator and tightened the belt so tight there was very little deflection...squeal stopped.

But that was a 2.3 and you can actually get a pry bar under the alternator on them. So I'd say take as much tension out of the alternator belt as you can...when you can and see if that makes it go away.

 

[ab_slack]

Alright, I haven't gotten this resolved yet and probably won't get back to it for week or so, so this can get moved out of the need it now.

I have a few leads and thanks everyone for the thoughts. I'll follow up when I get back to it.