[Vwdiesel] DI, DW in Rolling Stock (fwd)

Nate Wall natewall1 at yahoo.com
Mon Jul 14 07:34:16 EDT 2003

My mother\ was a chemist at one time and she used
"Distilled" and "Deionized" intechangeablly for "Pure
water", water w/ out salts. I guess reverse osmosis
and distillation achieve roughly the same results,
water w/ out salts in it. I'm not sure about the ion
exhange method, though.


methods achieve
--- Val Christian <val at swamps.roc.ny.us> wrote:
> The following is the simple answer on deionized
> water vs. distilled
> water.  I asked a chemist, who tries to keep our
> planes flying and
> his fleet rolling.  Doesn't own any vwdiesels,
> though.  Someday he'll
> see the light.   -Val
> --
> I too have pondered over what to use in my antique
> Volvo radiator.  I wonder what Mercedes and Saab
> recommend.
> What do they use in the BIG diesels??
> Maybe this is a question for "Car Talk" ??  Hehehe..
> (What does "brother Tony " use in his '63 Dodge
> Dart???)
> And those Soe-fee-yah Brothers  or is it
> Soe-Fye-yah?
> (I dunno if they're still on WHAM?)
> Gee, I wonder if Dr Mech-a-nic would answer e-mail?
> Deionized water is quite pure, but not 100%, and is
> usually produced by ion exchange in which the water
> is run throught a column of "zeolite" and other
> resins which hold Na ions
> and exchange them for the Ca and Mg ions which
> create "hard water" and resulting soap scum etc.  It
> may also refer to RO water in which reverse osmosis
> is used with a fine membrane that is so fine that it
> allows only water through it and not the heavy and
> large ions as well as organic molecules that could
> create problems.
> Distilled water is produced from steam generated in
> some way.
> pH is a factor in corrosion as well as ion content
> of water.  Water used must be most compatible with
> the alloys in the engine.  Gasket material used may
> leach some soluble materials. "Pure" water will pick
> up ions from the impurities in the metal.
> A light coating of some water miscible oil such as
> castor bean oil will prevent ion leaching and
> lubricate water pump bearings.  Buffers in the
> additive oil as well as in the antifreeze will
> control pH for a while.  Oxidation of any additive
> to radiator water will influence pH and metal
> longevity.  Complexing agents, chelates, will render
> some metal ions less active in solution and will
> influence corrosive activity.  (Remember the
> chemical activity chart from Chem 101?)
> Heat capacity of the cooling fluid is important as
> well.  50% glycol is generally used because of its
> heat transfer efficiency as well as preparatory
> efficiency.  (Desert dwellers should take note!).
> All the above are generalities and useful knowledge.
> I don't know specifics around pH and ion
> compatibility for alloy or cast iron engine blocks.
> We checked military vehicles for pH and dissolved
> material content.  I can't remember any numbers.
> Anti rust and water pump lubes (Castor oil) were
> occasionally added, but the radiator fluids were
> changed infrequently.
> I will bounce this back to you and to a few other
> "antique car" aficionados (In BCC
> mode for anonymity) in case they want to
> correct/modify this old man's statements.
> Comments car fans?  What works for you?
> George (Keep 'em rollin'!) Braidic
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