Michael,
You could try doing a leak test into the cooling system past the head
gasket.
Some compression testers have an air line fitting on the end to allow this.
Bring engine up on TDC firing position for cyl#1, insert compression tester,
attach air line with 100 psi.
check cooling system pressure with a gauge.
do the same for each cylinder (at TDC) to see if you can get any rise in
cooling system pressure past the gasket.

Leak down on cylinder will not work because the rings or valves can offer
small leakage and not validate the head gasket as the reason.

This may not work if the head gasket is only leaking under extreme pressure
at this time, ( it will get worse) 100 psi is minimal compared to the psi
present on the headgasket during combustion.

On a pressurized cooling system air has to get in somehow. if you have a
leaky hose it will tend to produce a coolant leak out rather than suck air
into the system..

Another method is to have the air in the coolant tank and or / coolant
analyzed by a smog sniffer or equal. if it has hydrocarbons in it, the head
gaskets are leaking.

Doug

----- Original Message -----
From: "MICHAEL POPE" <raskayamon@MSN.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, March 28, 2004 2:01 PM
Subject: Air in Cooling System/ 89Westy

Well went to N Georgia for the weekend 1 1/2 hours away. By the  time we got
there, overflow tank was 1" from top of tank / ex pan tank was pretty much
empty. Let sit overnite still the same in the am. At this point from past
experience I must fill and bleed system to get coolant to proper levels or
would fill to brim and spit coolant before I could get home. I am leaving
overflow between min and max lines when I bleed/ have read the Bentley on
how to bleed, and it does the same thing when I get it back from the mech.
After a bleed depending on how much we drive the coolant starts to move from
expan tank to overflow until it overflows. Happens every time within 300
miles of bleeding depending on how driven. Can drive around in town and at
50 or below and no problem. Could clogged radiator have created enough
internal pressure to blow gasket? It sure had me chasing leaks for awhile
before I fixed it. That is about all I can figure out..Have not visually
inspected heater cores.That is all that's left. We are about to throw our
hands up on this one.

Michael
89 Westy
Rosebud