[daroccot]

I've got to replace the coolant in my '93.

I've been reading lots about the different types of coolant out there, I'll group them into two broad types, Regular or extended life.

From what i've learned the regular (green stuff) has phospates and sillicates in it and isn't so good for the cooling systems. The extended life stuff (not green) has lower to no phosphate & sillicates, and is good for the cooling systems, (would however still replace every two years)...

now the problem/question.

If the car already has regular coolant in it it is not recommended to change to extended life as there is some sort of reaction that will enhance any deposits already present in the system, is this the case?? Also there was suggestion to run a weak acid solution through the cooling system before switching over, any one know what this acid solution might be?

So here's the question, do I just keep using the regular stuff, and change it every year, or should I go through the hassle of the acid rinse, flushing, and switch over to the extended life stuff (and follow a regular maintenance interval)

BTW the ratio of coolant to distilled water is 70:30 as I live in a harsh climate. Very Northern Canada winter 6 months of the year cold the other 6 months, sub-arctic really, winters average -25 with cold nights down to -50. Ask me why I live hear again???

thanks.