Slipping Drive Belt

[c_hernandez32]

My 91 explorer's drive belt keeps coming off. I drove it home from work and it fell during the drive. I put the belt back in the right order, but the moment I start it, the belt seems to fall off first at the water pump which forces it off the crank shaft. Is there a reason for it to be slipping off the waterpump? I guess I can replace the fan assembly, but worry that it is the waterpump. I have read up on replacing both, but I would rather take to a mechanic to replace the pump if necessary. Any thoughts or people in similar situations before?

 

[collegeexplorer]

Are you shure your belt tensioner is working correctly?

 

[c_hernandez32]

I simply returned the belt tensioner back the normal position. It seems to stay taught if the bolt is not turned. Is there something else I need to do to really tighten it?

 

[collegeexplorer]

I don't know an easy way to see if it is applying the correct tension or not. To my understanding though, its not uncommon for these to eventually fail. Not an expensive part either. When the belt is off, have you tried turning your water pump/fan clutch by hand. It should turn relatively freely.

 

[c_hernandez32]

It does turn, but not too freely. I also heard a grinding noise as I rotated it. Not with every turn, but it was noticeable. I reset the belt and turned it on. The explorer turned on, but died soon afterward (its been almost 2 weeks without being on). I have tried several times turning it one and each time, the water pump is the first to fall off followed by the crankshaft.

 

[Jason94sport]

I asked this not to long ago. There is no adjustment. The tensionor is what's there. That applies the correct pressure on the belt.
The belt is either stretched, or too long
The tensionor is shot
Or a problem with 1 or more pullies.

 

[collegeexplorer]

If you are unsure about the belt and tensioner, I might replace them first, just becuase they are cheap and easy to do. It seems like you might have found the problem though, if your water pump seems to be catching. I know mine spins pretty freely when i don't have the belt on and doesn't catch on anything.

 

[ma96782]

IF the belt is on correctly.........and the tensioner is working properly......you won't be able to move the belt by hand (unless you're super storng).......the tensioner keeps it tight on the pully wheels.

IF the belt does move (easily)........replacement of belt or tensioner is next........less likely but, possible, is a misaligned pully.

Aloha, Mark

 

[ma96782]

You said:

It seems to stay taught if the bolt is not turned.

".....if the bolt is not turned"..........the tensioner doesn't work by turning a "bolt."
The tensioner has a 3/8" square hole......you stick a 3/8" breaker bar into the hole and turn.

Aloha, Mark

 

[c_hernandez32]

It is a bolt or nut that you turn counterclock-wise to lower and allow the belt to come loose. The whole pulls moves down when pressure is applied, and returns to normal. I asked my brother-in-law and he thinks its the tensioner or the belt. I'll stop by Autozone to pick a new belt and tensioner.

 

[c_hernandez32]

Well it turns out that the belt that was on there previously was 1/2" too long. I tried to wrestle the new belt on, but will wait for a friend to help me put it into place.