The question is raised about where to tap into the cooling system to
measure pressure.

In a closed hydraulic system, such as the cooling system in our
Vanagons, the pressure everywhere in the system is very, very, nearly
equal.  Finding a place to tap off the system to sense the pressure can
be done easily enough at the connections to the heater, in the area
right ahead of the passenger seat.  A "T" connection can be inserted in
one of the heater lines there, it doesn't really matter which.  The
gauge will work equally well in either line.

You will see a difference, though slight, in cold and warm operation.
If you lose coolant circulation because of a slipping water pump rotor,
you get abnormally high pressure.  If coolant level is low, the coolant
level meter will alert you by blinking the led in the temperature
gauge.  If you blow a hose, likewise.  After a hot engine is shut down,
first you see a pressure rise, then a drop often to a low negative
pressure for a short time.  If you have engine compression leaking into
the cooling system you see abnormally high pressure, and then
overheating on the temperature gauge.

A pressure gauge is probably a worthwhile addition to our Vanagons,
given the complexity of the system, and the costs associated with a
severe overheating incident.

Chuck Hill

Chuck Hill