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Squealing, smoke, rubber particles and a broken belt

J

JWFokker

NAXJA Forum User
Location
Kingston, NY
So before I run out and buy a new belt only to have it break shortly after installing it, I need help figuring out what caused my serpentine belt to start squealing and throwing tiny rubber shavings, then smoking and finally breaking. The smoke seemed to be originating from the region of either the alternator or the fan. All of the wheels on the front of the engine were turning when it was doing this, so nothing is seized up. Any ideas what might have caused this?
 
If everything turns freely on the front, it seems like the belt may have been too loose. It seems like you need a new one anyway. If it squeels turn it off and readjust it. They need to be fairly tight.
 
JWFokker said:
So before I run out and buy a new belt only to have it break shortly after installing it, I need help figuring out what caused my serpentine belt to start squealing and throwing tiny rubber shavings, then smoking and finally breaking. The smoke seemed to be originating from the region of either the alternator or the fan. All of the wheels on the front of the engine were turning when it was doing this, so nothing is seized up. Any ideas what might have caused this?
Click to expand...

Check the alternator, idler pulley or A/C compressor.... One of the bearings could have seized up....
With the engine running and the belt driven by the crankshaft pulley...; which ever one that has stopped turning will cause the smoke and shredded belt....
 
x2 with winterbeater, and grab the pulleys and spin them to see if they are "good".
 
When you're checking the pulleys, look for side to side play/wobble, listen for any odd noises, etc as well. Assuming it's a serp belt, get a Krikit II (to check the belt tension) and a good quality belt. I went cheap on a belt last year, and it was pretty well shot 15K miles later.
 
Always keep a spare around, too... when I replace a belt the old one goes in the emergency kit if it's serviceable at all still.
 
CharlesS said:
Check the alternator, idler pulley or A/C compressor.... One of the bearings could have seized up....
With the engine running and the belt driven by the crankshaft pulley...; which ever one that has stopped turning will cause the smoke and shredded belt....
Click to expand...

How much force should be required to turn the alternator pulley? Everything spun with practically no resistance except for the alternator (and of course the crankshaft), which I couldn't turn with my fingers when reaching down from the top of the engine.

Edit: Also, I'm seeing some rust on some of the pulleys because it hasn't been driven more than a dozen times in the last two years. What's the best way to remove it? Wire brush? Or should I soak 'em in something like Evapo-Rust?
 
Last edited:
JWFokker said:
How much force should be required to turn the alternator pulley? Everything spun with practically no resistance except for the alternator (and of course the crankshaft), which I couldn't turn with my fingers when reaching down from the top of the engine.

Edit: Also, I'm seeing some rust on some of the pulleys because it hasn't been driven more than a dozen times in the last two years. What's the best way to remove it? Wire brush? Or should I soak 'em in something like Evapo-Rust?
Click to expand...




That alternator should be "heavy" but still spin very freely. The wire brush method I recommend to clean everything up...or spray paint hahahaha.
 
Stop by Autozone (whereever) and ask them if you can fondle an alternator, then you will know how it should feel and they will know you are a little strange. LOL!
 
Joshooha said:
That alternator should be "heavy" but still spin very freely. The wire brush method I recommend to clean everything up...or spray paint hahahaha.
Click to expand...

Hmm...so does this mean the bearing is seized or is the whole alternator shot?

Also, I'm looking at replacement idler pulleys and there are smooth and grooved pulleys. The one on my XJ is smooth, but does it make a difference?
 
Also check your harmonic balancer.
 
JWFokker said:
Hmm...so does this mean the bearing is seized or is the whole alternator shot?

Also, I'm looking at replacement idler pulleys and there are smooth and grooved pulleys. The one on my XJ is smooth, but does it make a difference?
Click to expand...

You would have to pull it apart to determine its condition.

I have seen the grooved pulleys in catalogs, I think it is determined by the belt routing--back of belt, smooth pulley, face of belt, grooved.

Take a really, really, really close look at the HB. They tend to only move a small bit at first and usually take out the serpentine belt when they do.
 
I've got a problem my I replaced my belt on my wifes 2001 xj and ever since it squeals on start up or under heavy load, I've already tried adjusting in and out, is there a spcific torque spec the idler pulley should be torqued to? I don't want to over tighten it and wreck the belt.
 
If the harmonic balancer has separated, (outside from inside) it will shred your belt by pushing it towards your timing cover. Sometimes it will take off half of the belt lengthwise and still work like 2 of mine have. It may not wobble though but will eventually cut into your timing chain cover.
 
FNCRZY said:
I've got a problem my I replaced my belt on my wifes 2001 xj and ever since it squeals on start up or under heavy load, I've already tried adjusting in and out, is there a spcific torque spec the idler pulley should be torqued to? I don't want to over tighten it and wreck the belt.
Click to expand...

Yes,you need a belt tension gauge!
 
I decided to ditch the alternator and pick up a remanufactured 136A Denso alternator for $65 shipped. I'll have to grind the brackets, but I'd rather have a newer, higher output alternator that's in much better shape than fix a 15 year old unit that's having problems. I've already got upgraded super heavy gauge battery wires, so $65 isn't a bad deal as far as I'm concerned.
 
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