For practical purposes there are two types of coolant used in most
cars, although some Euros specify low-silicate standards for their
vehicles. There is ethylene glycol (the old technology "green" type)
and OAT (organic acid technology) type. OAT is most commonly used today
and they are the "long-life" or "extended-life" type. Color is a dye
added to a basically colorless chemical compound; each manufacturer is
fond of their color. I would recommend draining the system and flushing
it completely if unsure of the type. Prestone, Peak and most of the
other major or house brands sold by your parts jobber will work fine in
a 50-50 blend with distilled water.
Jim O'Neill - Chino Autotech Inc., Auto Club SoCal AAR
SAE Int'l SoCal Section Board of Governors,
Vice Chair, Service Technology Programs
NASTF Service Information/Communications Committees
Auto Value/Bumper-To-Bumper CSC Nat'l Council
ASE CMAT-L1, CA. Smog Check Technician
AMI AAM Accredited Automotive Manager