Watter wetter doesn't do its job by making the guage reading drop, it does its work by increasing heat transfer between the water and the interior of the motor, radiator etc. Usually your cyl head temps will show a drop if you use implanted thermocouples. The idea is to reduce the chance that a hot spot will cause steam to form in the cooling system, which reduces cooling and causes a boilover. In pure water it works better because antifreeze already does a lot of the job... So the guage doesn't move much. But it still helps with heat transfer. And additionally its a great water pump lube. Dave __________________ Dave - PDX 1995 318ti - Active Black and Tan. 2005 330xi - Mtech 1 - 6spd - Orient Blue/Black |