Frank

whats your read on how often coolant should be changed?

-----Original Message-----
From: Frank Grunthaner <FrankGRUN@AOL.COM>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Monday, February 18, 2002 9:57 PM
Subject: Re: distilled water & wbx reliabilty

>I have missed most of this thread since, in my estimation, it has merited
the
>injudicious use of the delete key. As has all too much on list traffic
>recently!
>
>But a few points must be made here (and I am repeating info from
individuals
>laboring to infuse the discussion with facts):
>
>1. All water, not pathologically purified and stored under nitrogen or
argon,
>will contain a variety of salts ranging from simple carbonic acid
equilibria
>through the simple halides to dissolved divalent cations and even a variety
>of transition metals depending on the source and the storage media.
>
>2. All antifreeze formulations take this into account and have a number of
>chemicals in the primary solution so that pH and the dissolution chemistry
of
>aluminum, copper and iron are kept under control. The salts or hydrolyzed
>ions that define hard water can complex or remove these reagents. The
>reagents are often attacked by dissolved oxygen carries in the cooling
>system.
>
>3. The amount of control (translated into how long the additives protect
the
>cooling system from the effects of pH and aluminum oxidation) is a function
>of how hard the starting water is and how much oxygen is injected into the
>cooling system over time.
>
>4. When the complexation agents are depleted (or evaporated to dryness in a
>fixed air bubble in the water jacket of the head (example) a hard and
>generally insoluble precipitate results. Film, scum, bad. This deposit
>conducts heat poorly and often triggers cavitation. Bad.
>
>5. Most dissolution of block, head or other multimetal components (water
>pump) is triggered by pH changes or electrochemical redox reactions.
Aluminum
>is particularly vulnerable to attack with basic solutions (pH 10 and
higher).
>Copper is more readily attacked in acidic solutions, while iron goes either
>way.
>
>6. The singly most corrosive reagent in this system is ultraclean water.
>Ultraclean water at elevated temperatures will dissolve Teflon, silicon
>dioxide, silicon nitride, silicon carbide, hafnium nitride, etc., etc.
>Ultraclean water is literally free of ions (sub-picomolar), carbon residues
>(sub ppb) and dissolved gases such as CO2 and O2.
>
>7. So for longevity, use water of moderate hardness (5 grains or less - ask
>your water company) or filtered water as provided for steam iron
applications
>to mix the 50-50 solution with and Al compatible antifreeze. Bleed well
>(remove air pockets). Vent to an expandable bladder cell (stops the
>introduction of oxygen and CO2) with emergency pressure relief. For best
>results, use a gasifier and deareate the cooling system while bleeding.
>
>8. Switch to the Evans propylene glycol system and get rid of all this
>nonsense (for a price).
>
>RO systems good! Superstition bad! Down with political correctness!
Chemistry
>good, lawyers are politically correct.
>
>Need sleep.
>
>Frank Grunthaner
>