I too am a diesel mechanic. Nearly all pitting and damage done to diesel cylinder liners is caused by "cavitation erosion"
This process is caused by the super high cylinder pressures created during the combustion cycle of the diecel engine causing the liner to "flex' or "buldge". The liquid molecules surrounding the liner get "shaken" into creating tiny bublles on the surface of the liner,. almost like a can of cola. When these bubbles burst (explode, actually), they carry away a microscopic piece if the liner.
Eventually the liner will fail. This was a serious problem on high milage 7.3 liter Ford diesels. The two rear cylinders would fail, or if the engine came in for a rebuild, the two rear cylinders always needed sleeves. Obviously, the rear cylinders are farthest away from the water pump.
To help remedy this situation, higher pressure radiator caps are used and special additives are used in diesels to help prevent caviation erosion. The type of coolant used doesn't matter so much, the additive does.
Our newest Fire Engines hold 65 quarts of coolant.
Jeez, can you imagine how much it would cost to fill it with Evans Cool
--Mike