Good Morning Listers,

Water Wetter is a "wetting agent", this means that it changes the surface
tension characteristics of the liquid such that it no longer "beads up".
Soap works as a wetting agent.  When you spray water on a recently waxed
car, it beads up.  If you put soap in the water, it becomes a uniform film
over the surface instead of beading.

The theory is that by using a wetting agent in your coolant you create a
more uniform film of coolant against the critical engine surfaces,
improving heat dispersal into the coolant and reducing hot spots in the
engine.  Use of a wetting agent will NOT change the operating temperature
of the engine (this is controlled by the thermostat), but it will improve
the heat transmission characteristics of the coolant, and will reduce the
probability of air pockets in the cooling passages.

I use Water Wetter in both my Westfalia Syncro and my Mercedes 300TE.  I
have observed no change in the operating temperature of either vehicle.  I
have observed that the cooling system responds much faster than it did
previously.  For example, when you're stuck in traffic on a hot day, your
coolant temperature climbs and the radiator fan starts.  As soon as you
begin moving, the coolant temperature begins to decline and the fan stops.
When using the Water Wetter, the coolant temperature comes down much more
quickly, indicating that the cooling system is operating more effeciently.

I have been using the product for some time, with the appropriate
Volkswagen coolant, and have observed no adverse conditions in my cooling
system.  I have approximately 95K miles on my Syncro, and the engine has
not been serviced for heads (or anything else!).

Regards,
Jon