My 88 Wolfsburg Multivan was (presumeably) charged with autobahn coolant
originally, but the record of the PO shows a coolant change at 35k miles,
using old fashioned Presetone (not phosphate free).  I bought the bus at 50k
miles and continued to use regular Prestone.  Yup, the heads eventually
leaked and required replacement- at 125k miles.  Not bad in my view.  After
surgery, I have used Prestone phosphate-free and have traveled about 20k.
So far all is well (with respect to cooling system) and the engine runs
great.

This bus has always resided in the Denver area, where the water is quite
good, and has been consistently driven in a very conservative (slow and
easy) manner.
--
Mark A. Williamson
Denver, CO
88 Wolfsburg Multivan (145K)
95 Golf (56K)