I haven't had much time to work on the ol' Tahoe lately, but this afternoon I finished my tear down to inspect the bottom end. The bearings didn't look too bad for 375K miles, and I'd be tempted to run it as is, but I did find something that gave me pause for concern - there's a typical crack in the block originating from the outer main bearing hole on main cap # 4, on the cylinder 7 side. It's about an inch long:












So the question is now what should I do? I assume it would not be wise to continue running this engine with the crack, correct?

This is a 1995 929 block with 376K miles. I also have in my possession a 1997 506 block with around 100K miles; however, there is some issue with that engine - when I pulled it, it was running, but had no compression on cylinder 1. I never tore into it to see what the problem was. I am guessing it would be prudent at this point to go ahead and tear into the 1997 block and see what it looks like to see if it's a good candidate for a rebuild....

Casey