Don't switch from conventional antifreeze to Dex-cool unless the cooling system is very, very clean. Otherwise, Dex-cool can dissolve deposits and look like opaque mud. Cleaners used with it can also turn tiny leaks into big ones. Despite this, I've been running Dex-cool in my 1993 Ford and 1986 Toyota for many years, and both cars still have their original radiators and heater cores.
Pros: long-term reliability, original components maintained
Cons: requires clean system, dissolves deposits, can cause leaks
