Original message from Joe Fortino, "coolant leak under radiator."
My Reply:
Remove the front grilles, and let the engine idle until the radiator fan
comes on. The system is under pressure now and you should be able to see
where it is coming from.

Better yet, You should have the system pressure tested at a radiator shop,
unless you can borrow one. A pressurizing pump is attached to the expansion
tank, pumped up to a certain psi, and then if the needle doesn't drop within
two minutes, it's OK.

Check the bleeder valve on the top left of the radiator.
Check the heater hoses also.

Check your coolant hose connections above the spare tire carrier.
  it's a good idea to inspect where the rubber hoses connect to the two
coolant pipes that go to the rear.
And here is some advice for all-if you begin loosing coolant quickly or your
temp warning light is flashing, don't try to limp to a gas station, or home.
Pull it over and turn it off.
Overheating a waterboxer can lead to head gasket failure.

This happened to a friend, he drove 10 miles on almost no water, because
every time he pulled in to a gas station for water and filled the tank, it
all leaked out where he didn't see it-up under the spare tire.
We are finishing up a head gasket job on it now.

Robert
1982 Westfalia