HI Don,
I do agree with JC here, as the DEx-cool is good for up to 5yrs/100k. The non silicate formula is very good as lubricating the waterpump bearings, and prohibiting deposits inside the cooling system.
Obviously, its all relative on how the driver uses his car, however, I recommend that after 3 years, have the Dexcool checked for deposits, freezin, and boiling temperature.
Also, critical in changing any antifreeze is the need for distilled water.
Besttoyou, c4c5
