Tell ya a true story about distilled water.

When I was at Miramar (San Diego) I ran around with a guy who was becoming (and now is) an engineer. He was one of these guys who was difficult to convince the engineers didn't do everything right.

Had a 70 Chev 3/4T 4x4, bought new. We'd finally got him to put a 350hp cam in the thing after the factory cam went flat, but he refused to use an all steel cam drive. So around 74 just before I got out of the Navy, we had it torn down--to replace the phenolic cam sprocket.

He'd used 50/50 antifreeze and distilled water (San Diego water is horrid with minerals) and the INSIDE OF THE WATER PASSAGES LOOKED ABSOLUTELY LIKE NEW