Serpentine belt snapped

So yesterday I went out, got a new battery for my Jeep since the old one was shot (has been in storage for almost a year), did a bit of maintenance, checked oil and stuff. Then fired her up. Serp belt screaming and all, but it was doing this at the end of last summer when I moved it to the boat tent after it had sat for the summer. Figured the belt had dried up and needed replacing.

I expected the belt to scream so while i was getting a battery I picked up some serp belt treatment just to see if that could hold me over until I actually planned on getting the XJ back on the road and fixe it correctly with a new belt (just to shut it up while I pulled it to the driveway to work on it). It didnt work. I went out again today to make sure the battery was holding charge and it would still start (make sure I didnt have bigger problems and I have some draw on the battery). Started (a bit slower than I would have expected so I am hoping I dont have an issue, but still).

Was letting it run to make sure I got charge in there when suddenly it stopped screaming. Now the storage tent was a bit smokey, same as it was yesteday from the belt treatment coming off and the exhaust, etc (plus dust and dirt on the engine, just storage dust and crap burning off). I reved it once or twice (tapped the gas, not high revs) and tried turning the steering wheel to check if it would scream again under stress, and realized I had no power steering.

Thought maybe my PS pump bearings were shot and I had snapped the shaft to the pump and htats why it stopped screaming (that my PS pump was the problem), but I shut it down immediately anyway, maybe 5-10 seconds after it stopped screaming.. tops (after trying steering and revs), and it had run for maybe 20 seconds total

Went back up front, touched the belt... it fell off the pully. It had snapped. Now I dont think it was running long enough to do any damage. Not like it had even warmed up so the fan/water pump not tuning shouldnt have caused an issue. Now I am hoping the belt was just dried out bad enough that it was slipping and thats why it broke, which could also explain the battery having a slightly lower than expected charge (if the belt was slippng and the alternator wasnt turning well, it could have lost charge yesterday while I was working).

I never actually looked under the hood while it was running to see if the belt was turning at all or if it was slipping ever since the start, I would have gone deaf with the screaming right in my face. Can anyone think of any potential problems I may run into because of this? I never ran it for more than 20-30 seconds at a time and only ran it for a few 20 second session (after applying the treatment a couple times to coat the whole belt). now that the belts off I am going to check all the pulleys to make sure they turn alright and nothign siezed up, but is there anything else I should be looking for or should check before installing a new serp belt?

-Scott

check the harmonic balance, it may have seperated.

You should be ok with that little amount of time running. Mine snapped at the corner near my street, I drove it home, ran for about a minute.

Check the balancer, thats the big one that can cause these problems.

Also make sure to check the surfaces of all the pulleys. It is possible (tho not probable) that the screaming and breakage of the belt did not have the same cause. I'd bet on age/dry rot, but a nick or burr on a pulley(s) may have cut the belt.
Make sure all the pulleys are aligned properly as well. My last boat had left the factory minus the alternator shims and would eat belts.

now whats the best way to check the balancer? I am sure I can find it in the Haynes but my nice copy is in storage somewhere and the copy I keep in my Jeep (for emergency use if something breaks) is in sub prime condition so idk if the index/contents are still all there. Might have lost a couple pages somewhere in its life.

I planned on checking for burs, but planned on just checking the belt itself for gouges or something that says its facked. And how would I go about checking the allignment?

Edit: Did some poking around and found that using a straight edge should be fine for checking allignment. Still a little unsure on the harmonic balancer, I assume it is right at the crank shaft, but not sure exactly what I would be looking for. Is it located behind the crankshaft pully? is it part of the crank shalf pulley? etc etc?

Stick another belt on it and be done with it, I would however turn all the pulleys and make sure they are all free, the only one that wont' turn by hand is the one attached to crankshaft, thats the balancer, that you already know turns or the engine would not run. It is possible one of the idlers froze. No big deal, I replace them every time I replace the belt.
Tension on a brand new belt, 190lbs, tension on a used belt, 170, used belt is one defined as having been run for more than 15 minutes. You can get a belt tension gauge at NAPA for under $15, it's called a krikit II.

RichP said:

Stick another belt on it and be done with it, I would however turn all the pulleys and make sure they are all free, the only one that wont' turn by hand is the one attached to crankshaft, thats the balancer, that you already know turns or the engine would not run. It is possible one of the idlers froze. No big deal, I replace them every time I replace the belt.
Tension on a brand new belt, 190lbs, tension on a used belt, 170, used belt is one defined as having been run for more than 15 minutes. You can get a belt tension gauge at NAPA for under $15, it's called a krikit II.

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I like the sound of that reply a whole lot more, alot less time/money involved. haha. I will definately be looking stuff over, if something looks out of place I will look into it more, but will it be obvious if the balancer is facked, aka can I take a look at it and say "eh, looks good" or is it something that needs to be removed to really take a good look at it? I was originally going to just go to autozone and pick up a belt and throw it on, not even ask here since its kinda a trivial replacement, just figured I should cover my ass incase snapping a belt and losing the tension on the crankshaft pully would cause anything to come lose or whatever.

I usually check the balancer by laying under it and visually checking to make sure it is not leaning any direction. If it is bad it could be rubbing the timing cover.

Alright, thanks, if its not raining out again tomorrow maybe I will get to check it. ::crosses fingers:: comeon Jeep, you've held strong so far, lets keep going.