why distilled water?
tap water contains varying amounts of minerals and ions, as well as chlorine and sometimes heavy metals. also the pH of tap water may vary from acidic to very base. the minerals in the water will deposit themselves in the cooling passages of the engine and radiator, and eventually build up and reduce the efficiency of the system. worse than this however, the minerals and ions may react chemically and electrically with the aluminum and copper components in the cooling system, and set up an electrochemical process known as bimetallic corrosion which will actually accelerate the failure of these components. this process can be detected with the voltmeter test described above, and if a voltage higher than 0.500 VDC is detected, a very damaging bimetallic corrosion process is at work eating away your cooling system! distilled and deionized water contains no minerals, heavy metals or chlorine, and has a neutral pH, so it is the best fluid for your system.
