This Stuff Works! I was skeptical at first about this product - but I noticed Fire departments using a surfactant like this in the Pumper to help them extinguish fires faster. The surfactant breaks the surface tension of the water and allows it to surround and engulf the burning object better....it makes water "wetter"
So, I figured the principal was sound - and I tried it out in our run-hot prone Porsche® 928. It WORKS. I have used it now in the race car for 2 seasons with no over-heating, and in my street-driven Porsche® 928 also.
Have a look at the photo attached - that's the 928 at idle with the AC on, on a HOT day. Water Wetter moved that temperature needle about 5 to 10 degrees to the left from where it used to be. Cheap insurance against over-heating, warped heads and engine repairs.
One bottle is enough for your 928 cooling system. If added direct into the radiator, you will see the results that day. If added into the coolant reservoir, allow time for the chemical to distribute itself into the system fully. Supercharged users: does a wonderful job in the air-to-water intercooler system too!