[crashz]

Hi Ken,

Most likely the green antifreeze that you drained out is the standard stuff. "Heavy duty" may just imply a more robust additive package that retards cavitation and corrosion. Which if you are draining at only three years is going to be fine anyway. Long life coolants are often of a modified OAT technology (think Dexcool) that have been refined over the years to actually work pretty good. These are usually colored orange, red or a light yellow. You don't want to mix these with the standard old glycol antifreeze because gelling is a real problem. But you said it was green coolant, you should be safe.

Check with your owner's manual to match the specification on the collant with what you have used. 99% of the time you can go by the rule: green to green, orange to orange, etc.