Guys and Gals, if your belt tensioner looks like the left one in the following picture,
my advice to you is to change it quickly. My 2000 Coupe threw the belt off, so I bought
a new one. The old one still looked good, but I didn't want to trust it. Then the new belt
got thrown off, and I started to look at other things. The tensioner on the left is what
I finally decided was the culprit, and changed it out. 20 minutes is all it took, and the
belt hasn't been thrown off since. I've looked at about 10 or 12 LS1's since the
problem and none of them showed the same wear as my old one. The tension on the old one
seemed to be as tight as on the new one, so I don't think it was losing tension
and allowing the belt to come off. When I was looking at it, with the engine running,
the belt was moving towards the front of the water pump pulley. I expect that at some
point, it got too far forward and got thrown off. With the new tensioner on the engine,
the belt rides true and in the center of the water pump pulley. I'm the 3rd owner
and don't know if this is an original tensioner or not, but with only 45K on it I suspect
that it is.
Andy
