Found this amongst my files - info on auntyfreeze and coolant mixtures from a US source, makes interesting reading if you can last that long!
Date: Fri, 6 Oct 95 08:29:31 CDT
From: "Dan Houg" <
HOUGD@mdh-bemidji.health.state.mn.us>
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 hard 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
aluminum 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 they 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 combination
with other inhibitors is the best formula to prevent cavitation erosion
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 silicates.
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 pass
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 are 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 other 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
antifreeze 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 borate, which
is used in all leading American (and VW) antifreezes. Peugeot has not
announced its reasons, but they reportedly are based on laboratory tests
with no more real-world meaning than the VW tests have. According to one
American antifreeze manufacturer, Peugeot uses a benzoate-nitrite formul
"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 in the Peugeot engine it was buying.
Chrysler will use American antifreeze as factory fill and approve
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 cooling
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.
=========================================================================
Date: Fri, 6 Oct 95 08:58:41 CDT
From: "Dan Houg" <
HOUGD@mdh-bemidji.health.state.mn.us>
Motor magazine
Oct. 1982
Solder Bloom -- by Paul Weissler
The quick move by American antifreeze makers to formulations that
provide good protection against aluminum corrosion has, to date,
apparently forestalled a problem. Even the VW antifreeze has
apparently been successful in this regard. There do not seem to be a
lot of radiators being plugged by aluminum particles transferred from
the cylinder head.
However, another cause of plugging persists; high-lead solder corrosion,
called solder bloom, in the conventional copper-brass radiator. This
corrosion shows up as a white deposit that can "bloom" over the tops of
the radiator tubes, blocking them.
It's a problem that has nothing to do with the engine but results from
the type of solder used at the tube-to-header joints, and in some cases,
the way the solder is applied. There's no antifreeze inhibitor formula
that seems to be able to stop it cold for long periods.
The problem of solder bloom is also unpredictable. Some radiators in
some models years are apparently more prone than others. In any case,
the problem usually takes several years to develop, and you can see it
through the radiator fill neck.
Once you find it, about the only cure is to have the radiator cleaned.
The best results are obtained with an ultrasonic cleaner, although a
radiator shop's boilout tank may work if the cleaning solution is up to
proper temperature and the caustic concentration is adequate. Never use
the two-step oxalic acid cleaning method to remove solder bloom.
Although some pour-in radiator cleaners are recommended for solder-bloom,
the results are inconsistent and are poor if the bloom is severe.
The crimped-together and epoxy-sealed aluminum radiators do not
encounter the solder bloom problem. However, their durability is yet
to be proved. The early Rabbit and Scirocco radiators, for example,
may be failing at a rate higher than conventional radiators,
according to the National Automotive Radiator Service Association.
There failures are primarily perforation-- that is, corrosion of the
aluminum tubes starting from the inside and coming through. There is
some indication that VW aluminum radiators aren't tolerant of cooling
system neglect. VW's failure to prescribe cooling system flush and
fill intervals may be a factor.
=========================================================================
Date: Fri, 6 Oct 95 09:19:02 CDT
From: "Dan Houg" <
HOUGD@mdh-bemidji.health.state.mn.us>
The following is a summary from Prestone Corp.:
-PG IS LESS TOXIC TO MAMMALS
-BOTH RELATIVELY NON-TOXIC TO AQUATIC LIFE
-BOTH READILY DEGRADE TO CO2 AND H2O
-PG IS LESS EFFECTIVE AT LOWERING FREEZING POINT AND RAISING THE
BOILING POINT OF WATER
-PG IS MORE VISCOUS AT LOW TEMPERATURES
-PG CONCENTRATIONS CANNOT BE DETERMINED WITH HYDROMETER
-PG COOLANT IS A POORER CONVECTIVE HEAT TRANSFER FLUID THAN IS EG
COOLANT AT SAME CONCENTRATION
-PG COOLEANT PROVIDES COOLER METAL TEMPERATURES AT CYLINDER HEAD HOT
SPOTS UNDER BOILING CONDITIONS THAN DOES EG COOLANT AT SAME
CONCENTRATION
======================================================================== 99
Date: Fri, 6 Oct 95 09:36:33 CDT
From: "Dan Houg" <
HOUGD@mdh-bemidji.health.state.mn.us>
The following info from Prestone Corp.:
TYPICAL NORTH AMERICAN COOLANTS
-phosphate and/or borate
-high silicate
-nitrate
-triazole
-antifoam
-pH 10.0-10.5
TYPICAL EUROPEAN COOLANT
-benzoate
-borate
-silicate
-nitrate
-triazole
-antifoam
-pH 8.0-8.5
PRESTONE Antifreeze
-phosphate
-borate
-silicate (high)
-nitrate
-tolyltriazole
PRESTONE LONG LIFE 4/60
-organic acids
-silicate (low)
-tolytriazole
-nitrate
-molybdate
Here is the formula of a typical antifreeze coolant concentrate that
is safe for aluminum components:
Wt. %
ethylene glycol 95.56
sodium nitrate .10
sodium molybdate .20
sodium tetraborate .40
sodium silicate solution .30
phosphoric acid .15
MBT (50% solution) .50
TT (50% solution) .20
sodium hydroxide .235
water 2.30
polyalcohol .05
dye .005
MBT (mercaptobenzothiazole) is a corrosion inhibitor for copper or
brass.
TT (tolytriazole) provides protection similar to MBT, but TT is more
durable at higher temperatures.
Nitrates are corrosion inhibitors for ferrous surfaces, and protect
from pitting and crevice corrosion.
Silicates inhibit corrosion on hot aluminum surfaces, and provide
protection from cavitation. Silicates also act as general purpose
chemical buffering agents.
Borates provide buffering and neutralizion of acidic and sulfurous
combustion gas by-products.
Sodium hydroxide helps stabilize pH.
Silicones are antifoam agaents which also slow the silicate reaction
with magnesium.
Polyalcohol supresses the formation of foam.
Phosphates provide general purpose protection for several metals and
are effective in preventing the cavitation-erosion damage of
aluminum.
========================================================================
(1983.5 - 1991 Models Vanagons only)
COOLANT/ANTI-FREEZE:
Recommended coolant/anti-freeze:
Autobahn ZVW-237-104
antifreeze & summer coolant
Phosphate free formula for use in
Volkswagen & Audi water cooled vehicles
Ethylene Glycol based, Phosphate free
recommended mixture:
not less than 40 percent coolant, not more than 60 percent.
sold at VW dealers only.
manufactured by BASF Questions? Call 1-800-669-2273
BASF Customer Service: 1-800-445-4134
BASF Marketing Service: 1-800-367-9865
BASF Technical Service: 1-800-521-9100
Info from Marketing Service: <as of 03/94>
BASF makes a 'generic' brand of GUARANTEED Phosphate Free
coolant called ZEREX EXTREME 450. It has been approved by
VW, BMW, MB, Audi, Saab, and Volvo. It is also GUARANTEED for
four (4) years and 50,000 miles. They said you CANNOT mix this
with any other coolant; you must flush the system and fill with
the new coolant/water mix.
Info from Tech Svc: <as of 03/94>
BASF makes two (2) european formula coolants. One is sold by
VW, Audi, and Mercedes Dealers. The other is sold by BMW, Saab,
and Volvo dealers. The reason for the phosphate free formula
is basically two-fold:
(1) Cosmetics: Hard water reacts with phosphates in coolant to
form scale deposits in overflow bottles. These deposits
could form in other parts of the cooling system, causing
blockage and overheating (see next part).
(2) Corrosion: Phosphates tend to aggravate any corrosion that
might already be present with any aluminum parts in the
cooling system. Aluminum Phosphate is formed, which is
insoluble in the ethylene glycol solution of the coolant.
The aluminum phosphate will tend to settle out in the cooler
areas of the cooling system, causing blockage. This can
cause overheating of the engine, which will accelerate the
aluminum corrosion. In other words, the corrosion will tend
to feed on itself until damage is done to the engine or the
coolant is replaced (refreshing the inhibitors).
Engine coolant should be REPLACED every two (2) years to refresh
the silicates and other corrosion inhibitors contained in the
coolant.
He was not aware of any problems with coolants containing
phosphates, but did say that if the coolant was NOT replaced
regularly, the inhibitors would lose their effectiveness and
become weak. And that weakness could allow some aluminum
corrosion to start, and become aggravated over time.
========================================================================
this is a letter written to Road & Track magazine, Technical
Correspondence column, for the July 1996 issue:
White Stuff
-----------
I used to think the white stuff that plugs up radiator tubes came from
impure water, but after using only distilled water and ethylene glycol
and still getting plugged tubes, I called a radiator shop. A spokesman
called it "lead bloom." He didn't seem to know where it came from,
though. My older cars and tractors don't seem to have this problem.
Could it be from the alumninum used in newer motors? I can't find
anybody who knows. And what can be done to minimize its formation?
---------------------
Mike McGuire at Unigard was also unfamiliar with the term "lead bloom"
but gave several clues as to the source of your "white stuff." Running
straight water or old, worn-out antifreeze or antifreeze diluted by
topping off with straight water corrodes aluminum and yields a pasty
white goop. Mike pointed out that the agents in antifreeze that protect
against aluminum corrosion -- silicates -- wear out, and replacing the
antifreeze every 30,000 miles or two years is the only cure. So, while
you may have freezing protection if your coolant is old, it won't
protect against aluminum corrosion.
Another source of white contaminants is silica dropout. This occurs in
all-iron engines running high-silicate antifreeze, where there is no
aluminum for the silicates to chemically work with. If you have an iron
engine, inspect the antifreeze label for a phrase about compatibility
with heavy-duty engines. It is a good sign that antifreeze is a
low-silicate blend. This is because the long-haul engines from Cummins,
Detroit Diesel and others are always all-iron, and require a low-silicat
antifreeze.
Just for the record, distilled water can cause its own problems because
it has such a low pH. Water will seek its own balanced pH, and when
distilled water is placed next to aluminum, it leaches the minerals it
wants from the alloy and black soot forms in the coolant. That's why
silicates are put in aluminum-compatible antifreeze; they're
sacrificial mineral deposits.
