Radiator Caps that saves engines.

No way we said, after hearing that a radiator cap may prevent hundred
of dollars in engine damage. But we were talked into testing it. And we
are convinced it works. All water-cooled aluminum and iron engines
experience electrolysis-anywhere from 2 to 7 volts. This Charge
actually pulls molecules away from aluminum, eating at cylinder heads,
engine covers, water pumps, radiator and heater cores. It's a leading
cause of mechanical breackdowns. The solution is a magnesium anode
built into radiator caps. It draws the current away from aluminum
geponents. The anode is sacrificed to prevent expensive repairs (Your
home water heater uses a similar anode, for the same reasons)
Nothing will eliminate all electrolysis voltage in the system, but
radiator caps will add years of life to your cooling system. When the
anode has been used up, about every year or two, you'll need a new
radiator cap. It's an inexpensive alternative to a new water pump, or
cylinder head.