My local Caterpillar shop will do an oil analysis. I haven't done one for a while, but it was something like $10 or $12 dollars the last time I did one.
An oil analysis will tell you how much bearing material, among other things, is in the oil, and give you a good estimate of the overall condition of the engine. It might be worthwhile for you.
Edit: I just noticed I hit 1,000 posts. Woo hoo!
