I thought that switching to the Audi engine would get rid of my coolant
problems in my Double Cab.  I am finding that it is over heating after I
turn it off.  I can drive for hours and the coolant needle stays at or
slightly below the red "idiot" light on the coolant gauge - basically the
same place it always is [ or slightly lower than what the wasserboxer was ]
.  But two minutes after I turn it off there is massive bubbling sound of
water boiling in the round expansion tank.  The first few times it did this
it spewed some [ 100ml ] coolant on the ground [ from the square top-up
tank ].  When the engine is cold the coolant levels are all where they are
supposed to be.  I noticed that my radiator fan never came on in the last
little while [ month perhaps ] so I checked the plug to the rad.  Pin 1 had
12V and when Pin 1 was bridged to pin 2 or 3 the radiator fan did come on.
So, I installed a new thermostat switch with a 85 / 95C "turn on" points [
the old one was a hotter rating ] figuring that there was no more air
moving over the radiator when the truck was stationary and the heat from
the rad was leaching into the engine and over heating the system due to the
fan not coming on.  When I replaced the switch I noticed a soft grayish
green film on the old switch.  Needless to say my truck is still over
heating when I park it and the radiator fan does not come on [ the radiator
feels only warm to the touch ].  The bubbling lasts for about 30 seconds or
so.  The out side temp is less than 10C.  And sufficient heat comes from
the heater.  Is it the green film making an insulating layer in the cooling
system preventing it from dissipating heat?  Is it my water pump packing it
in?

Please help!

-- David Marshall, Quesnel BC, mailto:david@volkswagen.org --
   -- 78 1.8L VW Rabbit, 80 2.0L VW Caddy, 87 Audi 5KQ  --
   --  85 1.8L VW Cabrio, 88 2.0L VW Syncro Double Cab  --
   --   Volkswagen Homepage http://www.volkswagen.org   --
     --  USE DAVID@VOLKSWAGEN.ORG WHEN SENDING PMAIL  --