Mix the water with antifreeze, and you have no problem.

The problem is that many typical antifreezes are not electrolytes, they don't dissociate into ions. Same is true of many typical surfactants.

Water, highly polar, really wants some ions around.

I kinda thought the DI was put in to ensure that deposits could not form because there was no mineral source from the water (main reason) and second to partially leach existing deposits (secondary and much smaller).

But until you do the experiment or encounter someone you trust who has done it I'll just have to think and listen and read and see what I can learn.