Here is a new one on me. I was being nosy at a local diesel shop in town. The mechanic had a 599 block torn down to the bare block sitting on the floor. No pistons, cranks, just open. I looked down into the cylinder bores and saw piston oil coolers. What!?!? I thought that was odd, looked at the casting number, yep, ended in 599 as well as the markings on the lifter valley. So, being confused, I dug around his shop and found another 599 block torn down, it didn't have the oil coolers.

Has anyone else ran into this? I think it might be a hummer thing, because this engine came out of a 1995 H1 Hummer (non turbo of course). But, it still had the 599 casting on the block, must have been an early early production engine (didn't last none the less). The engine was intact on the bottom end though, no cracking.

Just thought I'd share, I'll get pics next time I'm over there.