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Re: Boge and another question

> Been investigating the Redline MTL question and got the basic product
> lit from Redline. In it they plot the heat transfer characteristics of
> water, 50/50 mix, and a 100% gycol. Guess what? The best is plain old
> water! Which is to say... make a mix which minimizes gycol content but
> still provides adequate freeze protection. You'll be able to improve
> the efficiency of the cooling system that way.

True, water may have better heat dissipation properties than ethylene
glycol, but don't go below that minimum concentration recommended by Audi.
The anti-freeze serves more purposes than its name indicates. I have read
that many cars depend on it for lubricating the water pump bearings and
that anti-freeze also contains corrosion inhibitors to prevent scaling
and salt deposits in the engine coolant passages. The corrosion inhibitors
lose their efficacy after going through a certain number of
heat/cool cycles and is one of the reasons why it is recommended that
the coolant be replaced about every two years.

In my own experience, I had bought a used Mazda 626 several years ago.
The previous owner had put water in the cooling system instead of the
glycol/water mixture. I don't know how long he had run it that way but
I flushed and filled the system correctly. Ran okay for about 20K miles
and then a whole bunch of overheating problems started. Anyway, I had a
blown head gasket and also needed to replace the radiator (whose passages
were clogged with scale/deposits) with only about 62K miles on the car.

Zafer Mehmood				   AT&T Bell Laboratories
zm@mhcnet.att.com			   Murray Hill, NJ