i have proof it works.
Back in my dsm days, i had the CEL set to engage via DSMlink when the temp reached 230*. well come summertime with the FMIC hogging all the air for the radiator, the CEL went off almost instantly. Logged in dsmlink, temps would hover around 235 during idle in hot (100*) cali summer traffic, and come down to maybe 220-225 during cruising speed. this was with both fans engaged at full blast at all times.
I did a standard cooling system tuneup (changed fluids, 30% coolant, 70% water mix, 170*Tstat, new cap) and saw an average 10* drop, logged via dsmlink of course. On a whim i heard about this water wetter and what it does, and poured a whole bottle in.
After a day i was recording 210* at idle in even hotter cali weather (it was 105* that day with zero wind), and 190-195* at cruising speeds. I also fabbed up a little shroud that pulled a bit of air from under the car into the radiator which brought cruising temps down even more to 185-190* during freeway speeds.
