Chris, here are a couple of excerpts re distilled water. Although I did
not say,
> I know you know a lot about water
>chemistry, so I would like to hear the explanation.
>
this is part of the subject matter I mentioned.
Since you have a source,
>We just had this
>discussion last year on the E-type listserve and the PhD chemists said this
>notion and that de-ionized water is hungry for ions is a common
>misperception but codswallup.
>
lets here from you and what they say.
Larry
>
> [MB] 1.2.1 Fresh water specifications/treatment of water
>
> David C. Allen mercedes@hsb.baylor.edu <mailto:mercedes%40hsb.baylor.edu>
> Thu, 21 May 1998 21:35:42 -0600
>
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> ------------------------------------------------------------------------
>
>1.2.1 Fresh water specifications/treatment of water
>
>Clean water which is not too hard, should be used for processing the
>coolant. Drinking water frequently, but not always, satisfies the desired
>requirements.
>
>Not suitable are seawater, brackish water, brines and industrial waste
>water. The content of dissolved substances in the water may differ very
>greatly depending on its origin (ground water, spring water, surface water)
>and is of particular significance for the occurrence of corrosion.
>
>Water which is too hard is detrimental because of the possible formation of
>scale or sludging. Salt contents, primarily chlorides, greatly promote
>corrosion. If doubt exists, the water should be analyzed. Information
>regarding the quality of drinking water can be obtained from the local
>water works or the water supply company on request. If no information is
>available regarding the quality of the water, distilled or fully
>demineralized water should be used.
>
>If the water does not satisfy the permissible analysis levels, it should be
>processed in a suitable manner for even good anticorrosion/antifreeze
>agents are affected detrimentally in their corrosion-protecting effect if
>the quality of the water is poor. Should it not be possible to soften the
>water, the water should be set to the permissible hardness by adding soft
>or distilled (fully demineralized) water.
>
>An excessively high content of chloride or total ions in the water can also
>be reduced by adding fully demineralized, in other words on-exchanged or
>distilled water.
>
>Depending on the impurities which are present in the water, it may be
>necessary to use appropriate processing methods (desalination and softening
>or partial methods). Information regarding processing the water can be
>obtained from the local water works or water supply company as well as from
>companies and engineering offices specialized in this field.
>
>Depending on the coolant composition, the analysis values of the water
>should be within the following limits:
>
>1.2.2 Fresh water quality with coolant composition conforming to par 1.1.1
>(car and CV engines)
>
>Total of alkaline earths (water hardness): 0 to 3.6 mmol/l (O to 200 d)*
>pH value at 20C: 6.5 to 8.5
>Content of chlor ions: max. 100 mg/I
>Total of chlorides+sulfates: max. 200 mg/l
>
>* Common designations for water hardness in various countries:
>1 mmol/1=5.6' d=10' f--7.02' e=100 mg/kg Ca C03.10 d
>(German degrees=10 dGH)=1,780
>(French degrees)= 1,250 e
>(English degrees)=1,79 mg/kg Ca C03 (USA hardness).
>
>If doubt exists, contact Daimler-Benz AG, Department EP/QWB
>(Betriebsstoffe), H 120, D-70546 Stuttgart.
>
>
Chris Thompson wrote:
>Distilled water seeking minerals? It's been - oh never mind - since I took
>chemistry but this doesn't make sense to me, Larry. We just had this
>discussion last year on the E-type listserve and the PhD chemists said this
>notion and that de-ionized water is hungry for ions is a common
>misperception but codswallup.
>
>I always use distilled water in my fleet.
>
>>
>> [MB] MB Coolant, and a Chemistry question
>>
>> James Mahaffey mercedes@lister.privatei.com
>> <mailto:mercedes%40lister.privatei.com> Fri, 22 Oct 1999 14:20:46 -0400
>>
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>>
>> ------------------------------------------------------------------------
>>
>>Ferrell,
>>
>>Antifreeze is a dangerous topic, but I'm feeling wreckless today.
>>
>>Your MB antifreeze is 94.0% ethylene glycol, a non-evaporative alcohol,
>>derived as a byproduct of the soap-making industry. 3.5% of your MB
>>antifreeze is water, and 2.5% is corrosion inhibitors and an anti-foaming
>>agent. (My data is about 5 years old - it could be propylene glycol by now.)
>>
>>MB antifreeze is built to ASTM (American Society for Testing and Materials)
>>standards. The standard (ASTM D-1384) corrosion weight-loss for brass (as
>>the corroded tip of your mono-valve) is "10 mg/coupon" which I think means
>>10 miligrams/cooling-system load. pH (ASTM D-1207) of antifreeze diluted
>>with water is 10.0 to 11.0.
>>
>>I wish that instead of selling antifreeze they would sell pre-mixed coolant,
>>because here's where the chemistry gets skewed. For example, why is there
>>an "anti-corosion agent" in antifreeze? Ethylene glycol is not corrosive.
>>Distilled water is not corrosive, so why anti-corrosive?
>>
>>But distilled water IS corrosive - more so than common ditch water. Pure,
>>deionized water is looking for ions, and it will take them out of the
>>aluminum in your radiator, before you can say "carbyloxilates." So, if they
>>assume you're going to use distilled water they put in a salt (corrosion
>>inhibitor), such as potassium sulfate. Unfortunately this skews the pH of
>>the mixture, which should be a neutral 7, towards the acidic, so they add
>>"reserve alkalinity" thus leading to the high pH.
>>
>>Other antifreeze makers sometimes assume you're putting in tap water, and
>>they anticipate the composition of your tap water by region, and even by
>>season. (Summer tap water has more chlorine in it, for example.) It gets
>>extremely complicated.
>>
>>But, why did you experience corrosion of the brass tip, which I suspect is
>>greater than 10 mg/coupon? Did you put in your distilled water, then mix in
>>the glycol? That could be disastrous. Mix it in a container outside the
>>radiator, then put it in the radiator.
>>
>>Personally, I always use tap water. I have seen what distilled water does
>>to aluminum cooling coils in nuclear reactors, and it's not pretty.
>>
>>Jim
>>
>>
>>
>
>
>Cheers
>
>Chris
>
>Larry wrote:
>
>
>
>
>>Steve, the Mercedes group is always against distilled water, as it is
>>seeking minerals, and the engine, and alum parts are the victim.
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