Engine change problem. Water pump impeller chewed up....Where's the pieces?

[Jake Raby]

Debris generally doesn't accumulate in water jackets.. What kills the bottom end is intermix.

Most debris ends up in the heat exchanger, internal passages and the 4-6 cylinder head.

The year of the engine has a huge impact on what the capillaries in the heads accumulate.

The pieces that cause the most damage are smaller than a pencil eraser, the big chunks can't make it into the cylinder heads at all.. The smaller the pieces the deeper they can go.