Engine/Transmission (1998.5 - 2002) Belt jumping a groove on Fan Pulley

[bnbrown]

On the wife's 2000 ever since we got the truck it has eaten the front edge off belts, I wondered where the previous owner had found a belt that was one groove narrow... but all you have to do is put a full width belt on and 200 miles later it is one groove narrower.

What I have already done:

-removed belt, checked all pulleys. All seemed tight and to spin appropriately.

-tried different brands of belt

-replaced tensioner assembly (now you need a 24" ratchet to get the belt on)

-replaced water pump



It is beginning to squeal when you throttle up, but not at idle or under no load (such as revving at idle) so it makes it difficult to pinpoint. A/C on/off makes no difference.

I did notice the fan drive pulley is closer to the bolts on the front of the motor than I am used to, it is slightly rubbing one of the cover bolts behind it. There is also now a slight ticking noise coming from the same area, I am assuming it is the sound of the pulley taping the bolt head.

I called cummins and they want $130 for the fan drive bearing, but I dont have a press to install it, and would hate to go to all that work if I am looking at the wrong thing...

so my question is: What else should I try before pulling the fan drive and replacing the bearing? is there something I am missing?

 

[Cummins724]

Have you looked at the harmonic balancer to see if it is seperating or loose bolts & wobbling while the engine is running. I would say that it is the bearing considering that you can see a problem with it hitting the bolt..... maybe even a bent pulley, but you should be able to see that with the engine running.

 

[CSnyder]

Just an FYI! You wont need a press for the fan hub pulley. They slide right off after you remove the bolts. Take a close look at your alternator bolts for misalignment. Hope this helps! Chris

 

[bnbrown]

I was thinking of that too, but the harmonic balancer still spins true as I can tell, my 99 the balancer looker more like a cam going around in there it was so bad when I had it replaced... The fan pulley spins straight, no room for wobble as it is scraping the dust off the cover bolts... guess it is down to pulling the fan drive off there...

 

[bnbrown]

Will take a look at the alt also, in the middle of moving from CA to CO so half the tools here, half there kinda deal... I guess I read the need for a press to reinstall the bearing on the first-gen forum... will give it a whirl. Thanks for the ideas.

 

[J.BURCHFIELD]

On the wife's 2000 ever since we got the truck it has eaten the front edge off belts, I wondered where the previous owner had found a belt that was one groove narrow... but all you have to do is put a full width belt on and 200 miles later it is one groove narrower.

What I have already done:

-removed belt, checked all pulleys. All seemed tight and to spin appropriately.

-tried different brands of belt

-replaced tensioner assembly (now you need a 24" ratchet to get the belt on)

-replaced water pump



It is beginning to squeal when you throttle up, but not at idle or under no load (such as revving at idle) so it makes it difficult to pinpoint. A/C on/off makes no difference.

I did notice the fan drive pulley is closer to the bolts on the front of the motor than I am used to, it is slightly rubbing one of the cover bolts behind it. There is also now a slight ticking noise coming from the same area, I am assuming it is the sound of the pulley taping the bolt head.

I called cummins and they want $130 for the fan drive bearing, but I dont have a press to install it, and would hate to go to all that work if I am looking at the wrong thing...

so my question is: What else should I try before pulling the fan drive and replacing the bearing? is there something I am missing?

Sounds like a pully out of line. A straight edge might tell the story. Stretch a string across the face ot the pullys if the straight edge is too awkward. You may have a wrong pully. I would check the part numbers. Maybe one pully is not on all the way. They get in a hurry at the factory. When something does not go on quite right they pretend it has, they won't be driving it.

 

[bnbrown]

Well... pulled the fan drive out, it put up quite a fight, couldnt get the fan off it, even tried to manufacture something to hold the pulley... but too much torque required. Wound up taking the whole assembly out, and taking it to a local shop, they pulled it apart, pressed out the bearing and pressed in the new one...
Pulley is no longer rubbing the cover bolts, but still seems awful close to the block, it does seem to line up better now, belt has so far stayed in grooves.
The queeling on the other hand is still there, no better, no worse... I guess maybe I will take the belt tensioner off, and get a replacement one. Seemed like it should have been keeping the belt a little tighter than it was. With just a little pressure on the wrench it took quite a bit more slack out of the belt.

 

[J.BURCHFIELD]

Well... pulled the fan drive out, it put up quite a fight, couldnt get the fan off it, even tried to manufacture something to hold the pulley... but too much torque required. Wound up taking the whole assembly out, and taking it to a local shop, they pulled it apart, pressed out the bearing and pressed in the new one...

Pulley is no longer rubbing the cover bolts, but still seems awful close to the block, it does seem to line up better now, belt has so far stayed in grooves.

The queeling on the other hand is still there, no better, no worse... I guess maybe I will take the belt tensioner off, and get a replacement one. Seemed like it should have been keeping the belt a little tighter than it was. With just a little pressure on the wrench it took quite a bit more slack out of the belt.

Sounds like you got it whiped

 

[BMote]

FYI. Had a similar problem with my fan and pulley. The fan is left hand thread and finally came off with hammer and chisel. The pulley was close to bolt heads, and poorly aligned. Pressed bearing into pulley further to give more clearance to engine. It would appear to me that there was no alignment groove, mark, c-clip, nothing to indicate where the bearing was supposed to go. Had it on and off three times, checking with straight edge for alignment with other pulleys, pushing that bearing around a little every time before I got it right. Sounds very much the same with your pulley. Check that alignment with pulley faces.

 

[bnbrown]

indeed that is what I had to do, pulled the fan drive off again, still couldn't get the fan off. pushed the bearing another 1/8" and no more jumping the groove.

However the belt is still screaming... brand new belt, re-replaced the tensioner, applied belt dressing... still screams. It will still only do it when accelerating, or throttling up a hill. A/C on/off still makes no difference. I did notice the voltmeter is varying by maybe a couple volts, most of the time rides just at or barely below the 14 mark, when I throttle up and belt starts whining it will go a volt or so over 14... at $200 I don't want to replace the alternator for nothing though, just not sure one of those autozone tests would actually provide useful results...

any ideas?

 

[J.BURCHFIELD]

indeed that is what I had to do, pulled the fan drive off again, still couldn't get the fan off. pushed the bearing another 1/8" and no more jumping the groove.

However the belt is still screaming... brand new belt, re-replaced the tensioner, applied belt dressing... still screams. It will still only do it when accelerating, or throttling up a hill. A/C on/off still makes no difference. I did notice the voltmeter is varying by maybe a couple volts, most of the time rides just at or barely below the 14 mark, when I throttle up and belt starts whining it will go a volt or so over 14... at $200 I don't want to replace the alternator for nothing though, just not sure one of those autozone tests would actually provide useful results...

any ideas?

Pulleys could still be out of line a little. Try some belt dressing, not that it will fix the problem but will tell you your pulleys might be out of line if the squealing stops for a while. It is not easy to get a straight edge in the pulley area. You might be able to use a string stretched tight and held on the face of the pulleys. You will be able to tell which one is out of line and how much. I does not take much to cause a squeal or if no squeal, excessive wear. Almost sounds like there is not enough tension. If you don't have a hand held Digital Voltmeter, they do come in handy for a lot of things and are all different prices from $20 up. If you get a reading at the altenator of 13. 8 to 14. 2 your OK. A reading at the battery terminals might be a half a volt less. TO AVOID INJURY STAY CLEAR OF THE FAN BLADES. A lady employee at my local Auto Zone was trying to hear a noise coming from the altenator of a customers car and her hair fell down on to the pulley and it PULLED her head down hard. It could have been worse. She is on light duty for a while. Maybe that is why they call it a pulley (pun intended)

 

[JFlagg]

I have just recently started having the same problem with the front rib getting cut off, but I don't have any squealing though. After reading this thread, am I correct in assuming its the fan hub bearing? I haven't checked to see which pulley is out of line, but one of them has to be. My new belt only last a few hundred miles before it was automatically narrowed.

 

[bnbrown]

On my truck it was pretty apparent which pulley was out of line, when you put a straight edge (i used a narrow level that had a magnetic side) it lined up a full groove behind either the crank pulley or the alternator pulley. I would put a new belt on and it would ride correct for a little while, then you would check after taking a nice drive and it would be sitting up on the lip of the fan drive pulley.

A continuation: I rechecked alignment, things seem correct as much as I can tell, swapped the alternator out of my '99 into the 2000 and took her for a spin. Thought I had it licked but gave her a good carbon clearing getting on the highway and she started screaming, seem to have to work at it a bit more to get it start squaking, but its still there... so I guess I will try to find a belt for no AC and give that a whirl... AC lost its charge mostly anyhow. Charged it up last spring, but barely cools now.

 

[J.BURCHFIELD]

I have just recently started having the same problem with the front rib getting cut off, but I don't have any squealing though. After reading this thread, am I correct in assuming its the fan hub bearing? I haven't checked to see which pulley is out of line, but one of them has to be. My new belt only last a few hundred miles before it was automatically narrowed.

A bad hub bearing would make noise. Most likely one of your pulleys is too far in or too far out. Stretch a string across the face or your pulleys to see which one needs to be moved and how much. A straight edge would be better if you could get it in there with it.