Alternator belt wearing out too fast

[Metallo]

Hi folks,

I am working on my 940 Polar, 2.0L Turbo SW of 1997 with 270000 on it.

The belt before my current one, it lasted 20000 Km
The one I currently have is on its way to break, after 9000 Km
The previous belts all lasted between 55000-60000Km
The belts I use are all genuine Volvo

Today, I finally got some time to remove the belt.

All the pulleys are perfect, no burrs.
I tested the core of the crank pulley, all good there.
However, I found that the alternator pulley is misaligned by 2-3 mm, so the alternator should be closer to the front of the car.

I also put a level on the flats and they appear to be skewed.
Now, I am not sure if this is meant to be like that, as also all the other pulleys are skewed in the same direction.

I also measured the alignment between the crank pulley and the A/C, it looks OK.

Now, consider that the alternator bushings are new, genuine Volvo parts.

At this point it is hard to say how to reposition the alternator given that there are no regulators for that kind of movement.
The only thing would be to undo the bracket from the block, there is a bit of backslash I could use with the bolts, but I seriously doubt the bracket has moved during the years, that area has never been touched in 24 years.
I am reluctant in doing that because if would also move forward the A/C which is aligned to the crank pulley.











Do you see anything I do not see from the images?

Thank you,
Alex

[Forrest]

I think from the factory the top alternator bolt is installed the other way around with the nut towards the back. However, I cannot believe this would make any difference in practice.

Are you using the correct belt? Volvo p/n 973487.

Does the alternator turn freely by hand? Have you replaced any bearings or parts inside it?

Do the other pulleys line up properly? Is the crank pulley properly fitted and torqued?

Are you slackening off the tensioner bolt when you’ve torqued the securing bolts?

[Laird Scooby]

Are you missing a spacer washer behind the alternator pulley?

The pulley seems altogether too close to the drive end bracket (case) on the alternator.

[Metallo]

Originally Posted by Forrest

I think from the factory the top alternator bolt is installed the other way around with the nut towards the back. However, I cannot believe this would make any difference in practice.

Are you using the correct belt? Volvo p/n 973487.

Does the alternator turn freely by hand? Have you replaced any bearings or parts inside it?

Do the other pulleys line up properly? Is the crank pulley properly fitted and torqued?

Are you slackening off the tensioner bolt when you’ve torqued the securing bolts?

Hi Forrest,

To your points above:

I noticed myself the bolt being on the other sde, likely when I changed the bushings I reversed it, anyways, it is now with the nut towards the back of the car.

Yes, the P/N is always the same for 24 years

Yes, the other pulleys align, although depending on the weather, the power steering/water pulley belt squeaks. If I spray some water on it, it stops for a few seconds, so that is how I know that is the squealing belt.

https://www.mediafire.com/file/5ea9t...62342.mp4/file

Yes, I do slacken the bolt, but this has no influence on the alignment, only on the tension of the belt.

Is it normal that all he pulleys are not perfectly leveled?

Alex

[Metallo]

Originally Posted by Laird Scooby

Are you missing a spacer washer behind the alternator pulley?

The pulley seems altogether too close to the drive end bracket (case) on the alternator.

Hi Laird Scooby,

Nope, the alternator is the genuine one, it has never been touched in 24 years.

Thank you,
Alex

[Forrest]

I wonder whether changing the bushings may have introduced a problem. I think over time as the bushings wear the alternator moves slightly further forward. Is it possible that someone has previously somehow moved the pulley further back on the alternator shaft to compensate for this? I don’t suppose you have another alternator you could try in its place?

[Metallo]

Originally Posted by Forrest

I wonder whether changing the bushings may have introduced a problem. I think over time as the bushings wear the alternator moves slightly further forward. Is it possible that someone has previously somehow moved the pulley further back on the alternator shaft to compensate for this? I don’t suppose you have another alternator you could try in its place?

I changed the bushings few months ago as an attempt to resolve the problem.
Honestly, if I install the new belt now, I will have to wait and see how long it will last this time, as this will be the first time that the new bushings and a new belt, work together.
It might be that the issue is resolved, but I am surprised to see the misalignment, even if it is 3mm, it seems a lot to me.
Likely adding a spacer washer to the right bushing (the one closer to the back of the car), it would force the alternator to move at least 2mm to the front.


However, it would not be 'by design' so I am reluctant to change anything.

I can try to put on the new belt and see how long it will last, but I cannot believe that the latest belt lasted only 9000Km due to the old bushings.

Alex

[Forrest]

I just played your video linked above. Are you sure all that noise is belt noise and not the harmonic balancer starting to slip? The crank pulley is made in two parts linked with rubber. As it starts to age the parts can slip relative to each other and make a noise like belt squeal. The belts don’t look like they’re too much out of alignment. There doesn’t seem to be much lateral oscillation. Hopefully someone who knows more about this than I do can pass comment.

[360beast]

Forrest has beat me too it, I'd say look at the condition of the rubber in the crank pulley.

[Metallo]

Originally Posted by Forrest

I just played your video linked above. Are you sure all that noise is belt noise and not the harmonic balancer starting to slip? The crank pulley is made in two parts linked with rubber. As it starts to age the parts can slip relative to each other and make a noise like belt squeal. The belts don’t look like they’re too much out of alignment. There doesn’t seem to be much lateral oscillation. Hopefully someone who knows more about this than I do can pass comment.

I drew a line with a marker and then I drove the car. No issue, the line is still perfectly matching between inner and outer core.
It was one of the first checks I did

Alex