squeal from serpentine belt on our M923A2

[maxtor]

Just started today. I sprayed belt dressing on it to no avail. Anyone else have this problem and had a fix for it?

 

[WILDBOY6X6]

I can say that the dressing is ok on a good belt if you just have rubber residue on pulleys, but if it does not stop the noise then it means the belt is dried out and need a new one. Another cause is a pulley is starting to seas up, the most common one to do this is the tensioner one. I would say remove the belt and spin each pulley to see if you hear any noise, if none install a new belt.

Steve

 

[M543A2]

I am not familiar with this series of truck but I can say I have had problems with serpentine belts in other applications because of the idler/tensioning pulley if it is spring loaded. They can stick on the pivot shaft and therefore cannot apply the correct tension force. If it is spring loaded make sure it moves freely on its pivot. Oil the pivot and move it until it frees up if possible.
Regards Martin Sacks

 

[maxtor]

Thanks for the information. I will check it out thoroughly.
Thanks again.

 

[74M35A2]

Start with the belt. Replacement available at NAPA, and always good to have a spare on board (old one). While off, spin each accessory pulley by hand and make sure none are overly difficult. If squeal persists with new belt, or returns shortly after, then replace tensioner. They don't last forever, and even though the spring load can feel "pretty good", the new replacement may be much stronger.

 

[aheilmann68]

I had a similar issue. Ended up being the tensioner pulley bearings. New bearings and good to go.

 

[maxtor]

Geeze,,, I have searched the sticky's, google, etc. etc. for Napa part numbers for the belt and tensioner for our M923a2 and I get many but different numbers for the belt and no numbers for the tensioner.

Is the sticky correct that the serpentine belt number is Napa NBH-080680 or another post that it is 4080675?

 

[maxtor]

Thanks again for all your replies.

 

[74M35A2]

I used the NAPA NBH 25080675HD. Has a green back side, and has fit/worked on my 925A2 without issue, including zero squeal.

 

[maxtor]

We should have the same Cummins 6CTA 8.3 engine. I will remove my belt and make sure it matches what Napa has.
Thank you.

 

[maxtor]

Well,,, I went to Napa and purchased a 25-080680 serpentine belt. I also checked both the tensioner and the other bearing pulley. Both were good. No play, and spun freely. I replaced the belt and all is good, no squeal. The original belt did not look that bad, but I guess it was. The belt was $51.99

Thanks for all the information.