engine and drivetrain Momentary squeal (of joy) ?

[deschodt]

I'm rebuilding confidence in the car (73) after it sat for over 2 years in a shop... I'm gradually driving it longer and harder... Tonight on the freeway, it started screeching while I was driving maybe 75/80 MPH (in 5th, didn't think of looking at rpm). Weirdly, the screeching diminished within 5 seconds and stopped before I could even slow down much or pull over. I got where I was going, took a look, nothing amiss, still had a belt and no smoke or anything... Drove it home later, made sure to beat up on it. Nothing... WTH ? I thought for sure belt/alternator, but I'm seeing everything turning correctly. 

 

The one thing I'm not sure about: the alternator seems slightly askew, but the belt alignment seems fine so I'm not sure, could be its shape... the alternator itself, not the pulley, seems not to be100% in perfect alignment (visually, not measured, see picture: the green arrow indicating the corner that seems to be a little too forward, and I can push it back by hand 5mm or so ). I'd say 95% aligned but looks like the belt is pulling one edge a bit. I could be dreaming this and it could be how they sit.. I can rock the alternator back a tiny bit. Not a huge amount mind, it could be OK for all I know if those are softer mounts... Should I just dress the belt a bit, or are there tests I can do to determine if alternator bearing or mounts (if that's possible) could be the issue? Anything else ? Water pump under there ?  No lights on the dash, low temps, never happened again... Start with a new belt ? What's the wisdom here ?   Thanks ! 

 

PS: unrelated but I had bought a fueling extension so I could fuel more easily, looks like a modern gas pipe you plug into the existing one... Doesn't work any better ;-(  You spill less, I'll grant it that. But filling still takes a week ! 

['76mintgrün'02]

It is probably time for new rubber bushings at the alternator mounting points.

Many people use poly bushings.

I am due too, but ordered one too few of the pieces.

My belt is slowly getting smaller.

Edited June 8, 2016 by '76Mintgrun'02

[PaulTWinterton]

Water pumps are disposable items.  They can start to squeal and wear out without warning.

 

There is a simple check to see if the water pump bearing is starting to fail.  Loosen the alternator, remove the belt and spin the fan/water pump slowly, If there is ANY binding at all, it could create the sound you heard.  

Edited June 8, 2016 by PaulTWinterton

[gastephens]

It is probably time for new rubber bushings at the alternator mounting points.

Many people use poly bushings.

Classic 2002 problem. Rubber bushings will wear out in a few years. Use the poly bushings.

Sent using Tapatalk.

[deschodt]

I hear you....  Just wondering why it stopped, but I'll get some bushings...

['76mintgrün'02]

It is my understanding that generators are always working and thus hard to turn, as opposed to alternators, which only 'work' when needed.

In other words, the more juice you ask for, the harder the alternator is to spin.

A momentary load on the alternator could explain the short squeal, but I do not know what that might be.

My neighbor's belt squeals just after he starts his Subaru, then stops.  My guess is that the alt is working to make up for the battery drain, due to the use of the starter, but that is just a guess.  It is a very common time for belts to squeal.  I have been meaning to help him with that.  I wish I could help you with this, but that is about all I've got... other than to say that not all failures/problems are linear; meaning getting progressively consistently constantly worse.  Sometimes they have a little issue, then seem fine, then the issue again; as the issues get closer and closer together.  I have heard an icky gravely bearing sound up front a couple of times, which could be alternator or water pump bearings?? but it goes away.  I expect I will be addressing both sets of bearings before too long, but in the meantime, I just keep listening for it to happen again.  You could try intentionally making the belt squeal, by turning on the fan and lights and rear defroster (if it actually works), which would add load and should make it squeal, if it is a belt issue.  You may be able to tighten the belt a little bit, but not too much, or you will certainly have pump, or alt, bearing issues.  I would just start with the bushings/mounts and hope for the best.

Tom

[deschodt]

Looking at the pic, do you guys see what I'm seeing or is that the normal stance? Looked to me like the alternator bottom edge (on pic) is being pulled forward so the thing is slightly misaligned...  Yes?  No ? I'm going to keep driving locally with this thing, before I dare taking it to the city w/ traffic jams... If it's gonna die (and I won't begrudge it after a 2 year slumber) I want to be closer to home ;-) 

[ray_]

2 minutes ago, deschodt said:

Looking at the pic, do you guys see what I'm seeing or is that the normal stance? Looked to me like the alternator bottom edge (on pic) is being pulled forward so the thing is slightly misaligned...  Yes?  No ? I'm going to keep driving locally with this thing, before I dare taking it to the city w/ traffic jams... If it's gonna die (and I won't begrudge it after a 2 year slumber) I want to be closer to home ;-) 

 

 

I would say yes.

 

You probably could find play in the alt mount after removing the belt.

 

As others have said, they all do that after a while.

 

Cheers,

[TobyB]

You need new alternator bushings.  Dear God, do not "stance" your alternator...

 

Quote

Loosen the alternator, remove the belt and spin the fan/water pump slowly, If there is ANY binding

OR wobble

that could make noise.

 

Same is true of alternators- if the bearings 'rumble', they're done.

 

I'm guessing loose belt, with angle.  And maybe older alternator bearings, too.

 

Or your center support bearing on the driveshaft.

 

Or the neighbor's cat that had curled up on the warm engine to take a nap...

 

t

['76mintgrün'02]

8 minutes ago, TobyB said:

Or the neighbor's cat that had curled up on the warm engine to take a nap...

 Ew, that actually happened to my aunt's cat.  Glad I did not have to clean up that mess.

Sorry, couldn't resist.

 

[jgerock]

By the looks of your bloated upper radiator hose, I recommend all your hoses be replaced---now that you are going to replace the alternator bushings.

Edited June 8, 2016 by jgerock

[JohnS]

The fan belt on my '73 would chirp/squeal every once it a while.  Belt was tight, bushings were good.  Turned out to be a very small leak near where the upper radiator hose connection is on the radiator. Was spraying a tiny bit of fluid on the belt after driving a while.  By the time I would open the hood to check it, everything would be all dried up and looking good.  Drove me crazy until it got worse and then it was obvious.  Any small leaks? 

[Buckeye]

Couple of things to check:

1). V belt tension should be in the range of 0.2 - 0.4" when belt is pressed in 

2). In the region above of the oil filter Area the tightening belt bracket is curved slightly to the back 

[roadhog0]

Make sure to get the right size belt! I found out there is a wrong size that will fit and run on an 02. I also drove thousands of miles (no joke) with the belt screaming like a banshee! It was too small (book size) and anytime you got over about 3500 RPM it would slip. Made for a noisy run down the highway!