I'm attempting to replace the serpentine belt on my 2000 Isuzu Trooper, but am not able to create enough slack in the belt by loosing the tensioner to slip belt on. I don't want to pry the belt on. Any suggestions?

There should be a bolt where the tensioner pivots

I think you are on the right track, suspecting the tensioner. It should spring back after you release it. There is a pretty heavy spring inside, it may have broken.

If your looking at your altenator you will have 2 brackets 1 holds the unit on the vehicle other bracket is sloted the sloted bracket is the tensioner besure to not overtighten leave a little deflection or you will wear out your altenator bushing /bearing.

This is no job for a novice. Take it to somebody that knows about these. NOT a simple job. You will need to replace water pump and tensioner also. http://www.youtube.com/watch?v=kjhNOVl1Tcc

1=crank
2=alternator
3=idler tensioner
4=IDLER
5=fan idler
6=air cond compressor
7=accessory drive belt(serpentine belt)
8=power steering pump

just in case this is the timming belt and pulleys

Sounds like your serpentine belt has become stretched over time and needs to be replaced. One of the pulleys is going to be spring loaded and placing a wrench on it and pushing or pulling(gently but firmly) will give you the direction to loosen it off. This belt tensioner is non adjustable .It either tightens the belt enough or it doesn't hence the squeal.Good luck.

Turn the bolt on the tensioner counterclockwise.

Use a wrench on the bolt. Slowly turn counterclockwise until there is enough slack to remove the belt. Hold in that position (if you let go the tensioner will automatically apply tension again). Remove the belt.

Do not fully remove the bolt as the tensioner will come apart. Just release the tension to the point where the belt is loose.

Simple job.

# 3...there is the tensioner.

I had the same problem when trying to replace the serpentine belt on my 2001 Trooper. The Maintenance book was very vague and I couldn't tell exactly how the tension was taken off the belt, but it did clearly identify the tensioner pulley. I first removed the pulley and looked for some kind of slot that would give me the adjustment I needed, but no slotted adjustment is present on the 01 Trooper. I had to do some research so I pulled of the tensioner assembly and found that there is a spring coil which keeps tension on the belt constant, and eliminates any belt alignment problems.

The Litens style tensioner uses a spring to apply pressure towards the serpentine belt. The way to relax the spring is to use your 14mm socket and ratchet and force the pulley down by driving the pulley nut in the clockwise direction. This forces the spring to compress and the pulley to drop giving the needed clearance to get your new belt in place.