I know I am beating this Water Wetter thing a bit, but it drives me nuts to hear products so thoroughly touted without some form of verifiable data that proves the claims.
My comment on water re WW was my understanding that WW requires per its instructions for use a ratio of 30% coolant to 70% water with WW added ... if this is correct, then the water component increase would seem to increase the cooling capacity in and of itself ...
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg