Date:         Fri, 6 Oct 1995 08:25:42 CST6CDT
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Dan Houg" <fairwind@northernnet.com>
Subject:      Antifreeze+phosphate article

Motor (automotive trade journal) Oct. 1982

The Great Debate -- by Paul Weissler

When your customers come in for a cooling system flush and a fill of
fresh antifreeze this fall, will you have the coolant recommended by
the car manufacturers for their automobiles?  Or for that matter,
should you?

Because of the increasing use of aluminum in engine components,
there has been a lot of reformulation of antifreezes.  And there's
also a whopping disagreement among domestic and some European car
 manufacturers on what should be used.

Here's the story behind the disagreement and some answers to
questions on which antifreezes to use, how much to install, and how
often to flush and fill.

The questions all started with the Rabbit and the Scirocco, VW's
entries in the water-cooled engine lineup.  Five years ago, VW put
out a well-publicized ban on antifreezes containing phosphate.  The
bas was reportedly based on laboratory tests of different
antifreezes, in which it was found that phosphate, a popular
corrosion inhibitor, would drop out of the antifreeze-water solution
in very ha rd water.

VW owners heard, quite correctly, that virtually all American
antifreezes, including Prestone II, contain phosphate.  So many
owners ended up at the VW dealer, paying up to $11 a gallon for
Autobahn brand antifreeze.

But, surprise:  In 1978, Chrysler introduced the Omni and Horizon
with the VW engine and recommended Prestone II.  The antifreeze
producer claimed it was effective in preventing corrosion in the
alum inum head.  This is important because aluminum particles can
deposit in the radiator tubes, causing plugging.  Chrysler based its
choice on its own tests of the different antifreezes.

By contrast, the Autobahn antifreeze, though not as effective in
preventing aluminum corrosion, holds the corrosion particles in
solution so the don't cause radiator plugging.

Union Carbide, maker of Prestone II, added its own explanation: 
Yes, some phosphate drops out of solution in very hard water, but
the problem is not a real-world one.  Further, phosphate in combinat
ion with other inhibitors is the best formula to prevent cavitation
corrosion of aluminum water pumps.  cavitation erosion is caused by
the forceful collapse of coolant bubbles against the inside of the
pump.  The force is great enough to cause chipping off of aluminum
particles.

GM has used aluminum water pumps for years, and its performance
standards for after-market antifreezes have always taken cavitation
erosion into account.

When Ford introduced its Escort in 1980, it published test
procedures and standards to cover both the aluminum head and
aluminum water pump for the engine.  The water pump erosion tests
included one for 1000 hours, a real toughie.

In addition to the Ford procedures and standards, the antifreeze
makers knew GM would have an aluminum head diesel V6 for 1982-- and
very similar after-market antifreeze performance standards.  That
pretty well dictated the decision for the American antifreeze
companies.  They could meet Ford and forthcoming GM standards only
with an antifreeze that contained phosphate and silicates.

Silicate is an established inhibitor of aluminum corrosion, but it
tends to jell as an ingredient in antifreeze.  Silicone compounds
are commonly used to prevent the jelling.  Union Carbide has used
silicone-silicate in Prestone for years, and current formulations by
the other leading makers-- Dow, Northern Petrochemical (Peak), BASF
Wyandotte, and Texaco (private branders)-- also contain silica tes. 
At present, all have aluminum protection formulas that meet GM
replacement and Ford O.E. specifications.  In some instances,
meeting the specifications is done by tweaking a basic formula to pa
ss some unusually difficult pert of a factory test.  However, even
if the after-market formula doesn't pass every part of every test to
the exact number, it comes close enough to ensure that there ar e no
real-world troubles with normal maintenance.

Chrysler has done limited testing but has to date approved a
Prestone formula similar to Prestone II and a BASF formula.  AMC's
Renault Alliance has some special requirements that pose problems
for o ther than Prestone II and BASF formulas, but that car probably
won't need its first flush and fill for a year or more.  By the time
the Alliance needs one, the industry will have tweaked the formulas
many times more.

GM uses some of the antifreezes that meets its replacement
specifications as factory fill on its aluminum-head diesel V6, a
break with tradition.  GM usually publishes a composition formula
for an an tifreeze and then takes bids from suppliers.  However, it
will not have the composition formula for aluminum-head engines
ready until next spring, because of delays in completing test work. 
However, even when the GM composition formula is announced, the
after-market antifreezes will continue to have GM approval as long
as they continue to meet the performance specifications.

There's an added touch of complexity in 1983, as Chrysler phases out
the VW engine and begins to use a Peugeot 1.6L, aluminum-head
engine.  Peugeot doesn't prohibit phosphate, but it doesn't allow bo
rate, which is used in all leading American (and VW) antifreezes. 
Peugeot has not announced it reasons, but they reportedly are based
on laboratory test with no more real-world meaning than the VW t ests
have.  According to one American antifreeze manufacturer, Peugeot
uses a benzoate-nitrite formula "that we consider inferior to all
leading American brands."

Peugeot doesn't sell many cars here, but you may have heard Peugeot
owners say they were warned by the dealer not to use anything but
Peugeot's own antifreeze, at a vintage wine price of $7 a liter.

Chrysler has reportedly told Peugeot it was satisfied with the test
results on American antifreeze n the Peugeot engine it was buying. 
Chrysler will use American antifreeze as factory fill and appro ve
comparable antifreezes for replacement, not the Peugeot formula.

So what happens if you use a leading American antifreeze formulated
to prevent aluminum corrosion in a VW or Peugeot car with different
factory antifreeze specifications?  The answer is that the cool ing
system will get the same good protection that domestic engines and
domestic cars with the imported engines get.  By the time the first
antifreeze change is due, the VW and Peugeot cars are out of
warranty, so even this cannot be used to defend the installation of
factory brands. 

-dan