[Commanderwiggin]

Lots of uninformed responses here. Been using a bottle of water wetter in my cooling system for my E46 M3 for over a decade with no corrosion or issues. It definitely helps with the added power and keeps the coolant from film boiling/nucleate boiling in the cylinder head while transferring all the extra heat. I've recently replaced my M2C top mount intercooler and added a bottle to both my intercooler cooling system and engine cooling system. There is no issue with the factory cooling system and hitting temperature targets of the thermostats. When used with oe coolant and distilled water I can verify that there will be no issue.

When used in any other manner like a pure distilled water solution with only water wetter as an additive I cannot comment.