Redline Water Wetter

[DeWitt Harrison]

On Fri, 8 Jun 2001 09:41:20 -0700, ScottFisher wrote:
 > [ ... ]

Interesting fact #1:

 > Here's the thing: RLWW doesn't fix problems in your cooling system -- it
 > does reduce your car's operating temperature if everything else is working
 > correctly.  The theory behind its operation is that it's a simple surfactant
 > or detergent, which reduces the sizes of bubbles that form from localized
 > boiling on the walls of your coolant passages.  This means more liquid (and
 > less vapor) is in contact with the cooling passage walls, which means more
 > heat can be transferred away from the metal.

Interesting fact #2:

 > When I used it in my '83 CGT, I had just acquired the CGT and it tended to
 > run a little warmer than I thought it should.  So I flushed out the coolant
 > and ran the Special Blue Stuff required by Audi for my car's engine
 > (phosphate-free antifreeze, Autobahn brand, purchased from the recently
 > retired Linda @ Carlsen).  It ran hotter after the RLWW, a LOT hotter, and
 > it ran hotter the more cold air went over the radiator.  Weird.  At this
 > point I looked at exactly how the CGT's cooling system worked, and started
 > scratching my head.

Interesting fact #3:

 > The Audi cooling system (at least on my I5 -- haven't traced down the V6 in
 > my wife's car) is backwards from all the other cars I've ever fiddled with
 > to any extent.  That is, on the Audi, hot water flows unimpeded from the
 > head into the top of the radiator at all times; the water is cooled, sinks
 > to the bottom of the radiator, and then gets drawn back in THROUGH THE
 > THERMOSTAT by the water pump.  (Other cars, if you haven't looked, have the
 > thermostat on the head, where it controls the flow of hot water out of the
 > engine.)  [ ... ]

I think these observations can be explained thusly (Mr. Myers, don't be shy
about jumping in with the correct anaylisis. :)    )
a. Thermostat on coolant inlet establishes constant _initial_ temperature for
engine coolant even though other conditions may vary.
b. More efficient transfer of heat from engine to coolant due to action of RLWW
implies greater temperature rise of coolant at outlet under high load 
conditions
(water vapor nucleation occurring).
c. The temperature gauge sensor is located at the _outlet_ so this temperature
rise is noted by the driver.

The question is, "Is this bad?"

Maybe not. Higher water temperatures in the radiator will promote greater heat
rejection to the atmosphere by virtue of a larger temperature differential 
between
the hot water and cooling air. Provided the water does not become so hot that
the vapor pressure exceeds the pressure cap's rating, and provided the system
is in perfect operating condition per Scott's caveats, a high gauge indication
could mean life is good in terms of reduced cylinder head temperature.

DeWitt Harrison
88 5kcstq