'97 throwing belt

'98 throwing belt

Hi all! I have a 4.0 '98 that is throwing my belt. It has thrown it three times when I lightly, yes lightly, gunn it to hit this little puddle on my half-mile dirt road to throw water up.
I took it rock crawling, gunned it all day up hills and stuff, never threw it once. It is only throwing it on this little hole. Every one tells me there is something wrong, but no one has any idea what it is. I hope someone here has an idea before I do something wrong and blow my motor! I do have something else to drive for right now, but I miss my Jeep!
Oh, and as far as the smart butts here are concerned, I have already heard the lines about it being a Chrysler product. :-D
Can anyone help me?

Re: '98 throwing belt

lisa said:

Hi all! I have a 4.0 '98 that is throwing my belt. It has thrown it three times when I lightly, yes lightly, gunn it to hit this little puddle on my half-mile dirt road to throw water up.
I took it rock crawling, gunned it all day up hills and stuff, never threw it once. It is only throwing it on this little hole. Every one tells me there is something wrong, but no one has any idea what it is. I hope someone here has an idea before I do something wrong and blow my motor! I do have something else to drive for right now, but I miss my Jeep!
Oh, and as far as the smart butts here are concerned, I have already heard the lines about it being a Chrysler product. :-D
Can anyone help me?

Click to expand...

Things that cause serpentine belt to fly off ..........
Improperly adjusted belt tension.

Harmonic Vibration Dampener lamination seperation ( yes, I made that up) which means that the flexible material between the outer and inner dampener rings is starting to squish out. This is usually visible with the engine running, the crankshaft pulley bolts to the dampener and it will appear to wobble when the engine is running.

Bent fan/pulley....look for a wobble here as well.

Defective belt tensioner

Looky there, not one SA response.........I must be sick or something. Hope this helps, now get it fixed and head for high ground..........glad I live in the mtns, you can have your gators, sand and 150 mph rotating rainstorms......

I would remove the belt and check ALL of the pullies for play(basically same advice as above). my Xj threw the belt a few times because the pulley on the alternator was loose because the housing had cracked. my freinds YJ threw its belt last weekend when the pulley on the water pump loosed up to much.

If it doesnt appear to have a loose link, then i would look at the tensioner. I'm not sure if it is the same on a '97 but the older XJ belt tensioner is a screw type not a spring so i wouldnt think that could very easily go bad.

Fan belt is thrown when you rev the engine.....
Remove the belt and check the pulley that is on the water pump.... The water pump bearing may be going bad, but the seal has not started to leak yet.....
The pulley will wobble like XJeeper said and this will throw the belt.
This happened to one of the SoCalXJ members while on our last outing to Los Coyotes Indian Reservation.

Charles

What/how are you using to set the belt tension ?

Thanks guys. I was getting worried. DH had posted the question on another board, but no one there had an XJ of the same year(s) and didn't know the answer.
I believe it is the water pump. I had overheating problems with it idling a couple of months ago, and a few times it looked like it was getting hot while running with the a/c on. DH said the water pump pulley looked like it was "off" last time he put the belt on.
Thanks again for your help.