[Oklahoma Wolf]

Is it raining by any chance when this happens?

I'd check all parts driven by the belt for loose bolts and/or damaged pulleys: AC compressor and bracket, alternator, water pump, and power steering pump. Something's out of alignment causing the belt to slip off. Could be the new tensioner is no good.

If nothing else, Dorman makes a shield that goes on the tensioner and idler pulleys (part #82570) that a lot of people use on these engines when they toss the belt in wet weather. My own Imperial got one after it threw the belt in the middle of a snowstorm driving through a snowbank, causing me to get severe frostbite. My crank pulley wobbles a bit too, but it doesn't seem bad enough to be a major problem. The belt's only come off twice in four years, both times driving in deep snow. Shouldn't be a problem for me any more.

 

[grayceworks]

It was raining this time, but not enough for the roads to be wet yet, it had just started. A few weeks ago, it was not raining at all - it was hot and dry. Previously, it was not usually raining, just once out of the 5 times.

The idler pully, the tensioner, and the belt were purchased from PEP boys and installed by the local repair shop I always go to. The alternator and crankshaft pully were replaced by Firestone, because we weren't anywhere near our local shop when those things happened. The belt has not appeared to be torn up or damaged when it came off, it simply slips off and slides over to the side of the engine compartment. They've checked that the tension is correct, they've checked that everything lines up, and that nothing is wobbling. I'm ready to pull my hair out. LOL

Is it raining by any chance when this happens?

I'd check all parts driven by the belt for loose bolts and/or damaged pulleys: AC compressor and bracket, alternator, water pump, and power steering pump. Something's out of alignment causing the belt to slip off. Could be the new tensioner is no good.

If nothing else, Dorman makes a shield that goes on the tensioner and idler pulleys (part #82570) that a lot of people use on these engines when they toss the belt in wet weather. My own Imperial got one after it threw the belt in the middle of a snowstorm driving through a snowbank, causing me to get severe frostbite. My crank pulley wobbles a bit too, but it doesn't seem bad enough to be a major problem. The belt's only come off twice in four years, both times driving in deep snow. Shouldn't be a problem for me any more.

 

[neon98rt]

use a gatorback belt. put a white paint line on the belt and pulleys to see if they wobble. Maybe put a straight metal ruler from one pulley to another to see if they are all even? Is your tentioner good?

 

[Bob Lincoln]

This is virtually always caused by the pulleys not all being in the same plane. A very slight misalignment, say, 1/8", can do it sometimes, and not be noticeable when you eyeball it or even hold a scale up to the pulleys.

 

[CHRYNY]

I had one with this problem. Turned-out one of the mounting brackets was slightly bent (maybe the alternator mounting bracket) causing a very slight misalignment.

 

[grayceworks]

Aha! Ok, so the crank seal under the timing chain cover is leaking and spraying oil on the belt. Also, one of the guys in our local repair shop said that he's also seen a lot of these cars throw off the belt fairly randomly anyhow, and he knew the exact part you were talking about Oklahoma Wolf, and he ordered it in for this afternoon. Also discovered a leaky water pump when the timing cover was pulled off... So will save some labor costs by getting it fixed along with everything else.

Soooo... the belt and pulleys were getting wet, even when it was dry out, and I didn't even know it.

I just hope it all runs ok once it's all back together, and that nothing got warped when it got hot. *crosses fingers*

 

[grayceworks]

Well... apparently when we overheated, we blew a seam in the radiator. That kinda sucked. But all fixed now, we hope. I noticed they roughed up the idler pulley so it's not shiny smooth any more? (I think that's the idler pully? ) Is that ok to do? I mean, I can see the reasoning, to make the pulley less slippery and help the belt grip, but will that cause wear on the belt?

Anyhow, seal is replaced, water pump replaced, bracket put on, radiator replaced... Between this repair, and the previous ones, I think the only thing left to fix is the power steering, and we've got almost a new car. lol

 

[Bob Lincoln]

Sanding the sheen off a pulley is standard procedure when replacing a belt, so it grips better.

 

[neon98rt]

I wouldnt care if it wears the belt faster , belts are cheap . having it fall off again isnt.

 

[B10alia]

No, it won't wear the belt down faster.

 

[grayceworks]

Just wanted to update this with the ultimate reason it kept slipping belts. There was a leaky seal around the crankshaft, and as the car would drive, it was spewing oil onto the belt. fixed the seal, no more issues, 2+ yrs now.