If the anti freeze doesn't say "phosphate free" do not use it, even if it is
Prestone.  I have seen three engines with less than 50k and their head bolts
were completely eroded to the point of parting. VW of A paid half the cost
of engine replacement even though warranty had expired in one instance. If
you have used any of the aforesaid product, run -don't walk - and purge the
stuff from your wasser leaker. Of course you can save about ten bucks a
coolant change - The choice is yours.. IMHO, the odds are stacked against
the savings paying off.. Of course there is always the lottery.  :-)
Your mileage may vary - Bud Yandell - Ft. Lauderdale