After speaking with the chem. engineer at Havolin responsible for their formulation (Havolin formulates for MB in America - BASF in Europe), I tend to think that Water Wetter is snake oil. I do believe that RedLine produces the best lubrication products. If Water Wetter works as claimed, the temperature gauge would register higher coolant temps rather than lower. WW does not improve the heat transfer in the radiator. It is claimed to improve heat transfer in the cylinder head by reducing nucleate boiling that prevents heat transfer. This would result in higher coolant temperatures. I have seen no real test results to prove their claims, only anecdotal testimony. The Havolin guy has been in the business for 30 years and has developed coolants for everything from autos to NASA space vehicles. His point was that if there were a compound that performed as WW claimed it would be in everyone's coolant formula by now. There are higher performing coolants available but they tend to be flamable creating other problems and liabilities.