[s-cars] Engine Coolant Flushing Procedure when switching to G12

[Dave Forgie]

The following is supposedly from a VAG Technical Service Bulletin
(TSB):

***********************

Unlike the previous "G11" coolant, this newly developed "G12" product
permits a cooling system fill that lasts the service life of the
engine and was designed with all-aluminum engines in mind.

Advantages over previous coolant:
Improved corrosion protection
Improve thermal stability
Improved heat transfer/control
Improved hard water tolerance
Improved environmental protection

CAUTION!G 012 A8D A1 must NEVER be mixed with any other coolant. Engine
damage will result! G 012 A8D A1 is red in color. The mixture of G 012
A8D A1 and other colored coolants is immediately identifiable by
discoloration (brown, purple etc.). If this mixture is used in an
engine, a foamy deposit will appear in the expansion tank/radiator. This
mixture is to be
drained immediately and the cooling system flushed as described
below.

Flushing procedure :Engine at operating temperature (older vehicles
(like ours) with heater valve: heater on). Drain coolant (lower right
side (left side -facing) corner of the rad (belly pan off) Attach hose
to nipple . Apply
compressed air to expansion tank or radiator to blow out remaining
coolant. Close cooling system, fill with distilled water. Run engine for
a minimum of 2 minutes. Drain water and apply compressed Air to
expansion tank a before close cooling system and fill with appropriate
mixture ratio of G 012 A8D A1and distilled water. Test drive, check
coolant level and add if necessary. Note:G 012 A8D 01 coolant may be
used in older
vehicles when the original coolant is drained and cooling system
flushed as described above. Inform customer that a new coolant Is used
and that ONLY water or G 012 A8D A1 be used to replenish. CAUTION! Never
re-use old coolant when performing
engine repairs.Dispose of old coolant properly. Flushing as specified
above, or engine damage resulting from the use of a mixture of G 012 A8D
A1 and other coolants is not covered by the
new vehicle warranty

Reference:  http://gti-vr6.net/library/engine/blue_or_red_coolant.html