My concern is that they are very emphatic not to mix it with water. But I don't know why. So, taskmaster is correct about his concern. But, I've been told that a big problem is making the switch; getting every last drop of water out of the system. They say generally the best time to start using Evans is when you have the motor disassembled, or rebuilt, and everything is dry. I got the impression it was primarily used in race applications; high heat for long duration.