This is common, it apparently upsets some folks so much that there are a few
class action attorneys trying to get a paycheck back against The General for
coming up with this horrible formulation.
However....
Despite the mud it does make, it apparently is very very good at remaining
anti-corrosive. Apparently the 'mud' it makes is small chunks or even a
slime coating of a silicon based product that cooks out of the formula over
time. Mechanics I've talked to said the mud has not been associated with any
corrosion related problems.
The $64,000 question everyone is posing to The General, is why this formula
is claimed to prevent corrosion for up to 5 years/150,000 when it begins to
precipitate the silcon granules many times before two years.
The end result from my research:
Dex cool is a very good product that produces a slime or even some small
amounts of 'silicon' mud.
Conventional wisdom is to stay with it. BUT change it every two years on a
flush and fill machine. The longer it stays in, the more it will precipitate
out the silicon flecks (what I found in my 98 Diesel Suburban.
SOOOO, the value of the 5 years is out the window if you have to change it
every 2 years.
I am looking for a suitable substitute due to this reason, but in no hurry
as the stuff apparently is very stable and anti-corrosive for a long time.

Mark Magee
90 CARAT 94K Miles
Kemah TX USA

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Bill Collins
Sent: Saturday, December 10, 2005 9:06 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Antifreeze

>  How about this orange stuff that's made for aluminum motors. Is it any
>good or does it have phosphates in it. It says it's good for all alum.
>blocks. Anybody use this stuff.

I use the Prestone extended life orange stuff.  I started using it about 8
years ago, when it specifically said phosphate free and did not say dexcool
compatible.  A few years later, they added the dexcool compatible statement.
I emailed them and confirmed that it could be mixed with the older stuff.

Since then, they have changed the bottle several times and I haven't checked
with them.  I recently removed the heads and found NO pitting or signs of
corrosion. (after 8 years and 40k miles)  I did find orange "mud" in the
expansion bottle and a thin orange coating on the inside of the water
jacket, so I flushed the system before re-filling.

I'm going to keep using the Prestone, but the "mud" bothers me.

Cost is under $10 a gallon at the local FLAPS.

Bill
>