Redline Water Wetter

[Brendan]

Well, if anyone's needing a replacement guide...
http://www.endosquid.com/audi/aud4kfix_radiator_moi.htm


 > 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