Re: Boge and another question

[zm@mhcnet.att.com (Zafer Mehmood [209])]

> 
> 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