George, I have used the Prestone pre-mixed for years with no problems.
Back in the 80s and early 90s, getting phosphate free antifreeze could
be tricky.  Today all modern engines have aluminum components (heads,
block, or both) so all antifreeze I have seen out there is compatible
with aluminum.  One of the things you still have to watch out for is
using tap water to cut the antifreeze with.  If your tap water has
minerals, etc. this could possibly cause an issue.  I usually use the
Prestone premix that you can get from Walmart for around $10 a gallon.
That way not only is the antifreeze right but the water in it is what
the antifreeze manufacturer recommends as well.  If you have to mix your
own, I recommend using distilled water to avoid any minerals or
chemicals.  Also changing your antifreeze every three to four years is
also critical because the corrosion inhibitor in all antifreeze breaks
down over time.  After this happens your antifreeze quickly turns into a
nasty soup that aids corrosion.  I have taken apart super low mileage
engines that have had the coolant rarely changed.  They looked like a
rat was living inside trying to eat his way out.

I still sell the blue stuff for folks that you can't convince that the
green stuff is OK.  I, however, use the Prestone and I have for many
years now with no issues.

Ken Wilford
John 3:16
www.vanagain.com

George Wietor wrote:
> Just bought another wasserboxer and am down to my last jug of the blue coolant from the dealer.
> Since it is time to flush and fill, I wondered if there was a cheaper, phosphate-free alternative.
> The PO had some Sierra in the Westy cabinet. Sorry if this has reached tire-like status, but I found nothing definitive in the archives so far. TIA/George
> '87 Van O'White
> '83.5 Lenny the Westfalia
>
>