I have been talking to some people that occasionally operate a historically significant diesel. They have been having some issues with the upper block and coolant leakage, which they attribute to electrolysis, more than cavitation. Has anyone else heard of this?

I had some experience, in an industrial setting a few years ago, with using deionized water. Would the use of deionized water, and maybe with the appropriate water treatment (for rust-) help with the electrolysis issue?

I realize using de-I water would not be practical in a steam locomotive, as the water (and literally dollars) would go up the stack, but in a closed system it would be a different matter. We were purchasing it in 55 gallon drums, and mixing it with a plant-based degreaser, as a replacement for acetone to clean raw steel. In five years we had no rust issues, while we did get flash rusting with acetone.

Any thoughts on this?

Is the corrosion widespread or confined to crevice areas like mating surfaces, EDM?

Water chemistry, low coolant flow, and air infiltration could all be contributing factors.

Perhaps some sort of small leak on the suction side of the pump pulling in air during operation? You'd see signs of seepage there from when the unit is sitting still.

We used hydrazine on the ship. LOL

There are several brands of diesel locomotive coolant treatment. D-I water is corrosive. The manufacturing plant that I worked at, had to use plastic piping for the D-I distribution system.

~35 years ago, borate was the treatment of choice, but that may be outdated by now.

Borate is still a good choice. Comes in sticks and powder. Not very expensive. Sticks are easier to toss into the filler neck.

Thanks for the responses. Yes, the railroad does use water treatment. The corrosion is within the block, and not at any mating surfaces. There are cracks in the block itself where it has become too thin. It can be repaired by welding (good boilermaker on the crew-), but I was hoping to find another long term, and preventative, solution.

I was not aware that D-I water was corrosive; you learn something new every day! As I noted before, in manufacturing we used D-I water and a plant-based degreaser (Benefect Atomic Degreaser) as a replacement for acetone for several years, and noted no corrosion on .006, .008 and .010" steel. Admittedly, the steel was not exposed to the water for very long. (And our process brine always was in PVC pipe or bronze valves.)

According to 20 Mule Team, they're using borates in nuke plants now...

https://www.borax.com/BoraxCorp/media/B ... f?ext=.pdf