In fact, Digifant tool guru Darrell Boehler has such a setup in his van.  I
don't remember where he tapped in, but there was some discussion a while back
about the proper place to do that.  I can't remember if there was a concensus.

Anyway, the idea is that you should see the pressure come up at startup and run
higher the faster the water pump spins with the motor.  You should also be able
to detect zero pressure (hose blowout, etc.) well before your temp starts to
rise.  In fact, the insiduous thing about a coolant system failure is that the
temp II sensor doesn't tell you the engine is hot because the hot coolant is
most likely not getting to the sensor any more.

Then, you can also monitor pressure loss when you shut down.

I haven't put it in myself, but it's on my to do list.

-Karl

> I've asked for a cooling system pressure check on a water cooled van =
> that I'm considering to see if there's any evidence of leaking cylinder
> heads - is this a good idea?, What is a = reasonable pressure to
> expect?=20 any better ideas? =20

Karl and Kristina Bloss, Trexlertown, PA
'87 Westfalia Weekender  "Beverley" - 194K miles
http://www.enter.net/~bloss/vw/
PA/NJ Vanagon owner's mailing list: http://www.enter.net/~bloss/vw/pavanagon/