loose balancer bolt
http://www.thunderracing.com/catalog...vid=3&pcid=299
It is possible to have a leak on the timing cover where the balancer comes out - I think it would have to be pretty loose though (wobbling). You'll have to hold the engine in order to get the proper torque. Don't know if you have an auto or a manual - but the easiest way is to get either a pry bar or a special flywheel/flexplate holding tool and brace the engine from the backside. That will keep it from rotating while you get the appropriate torque on it. If you haven't been doing it that way - there's a good chance it just keeps coming loose because you didn't tighten it well enough.
Here are your instructions for the pulley, taken from www.ls1howto.com:
Take your NEW crank pulley bolt and thread it in all the way by hand. Torque this bolt to 37lbft. Now, we need to stretch the bolt into place. Get your breaker bar and pipe extension, and try to turn the bolt 140degrees past where it is at now, keeping in mind the engine will be trying to turn some and those are degrees you can't count. Again, I always seem to get about 90-100 degrees worth (estimating, knowing what 90 degrees looks like) and leave it as is so don't worry about going crazy here.
Once the pulley is installed, the timing cover should be nice and centered around it, so we can now tighten all 10 of those timing cover bolts. Torque them to 18lbft on the bolts you can get a torque wrench on, and just make the others you can't get the wrench on about as tight as those. Reinstall the A/C belt at this time.


