I saw the replies saying check for exhaust in the coolant suggesting leaky
head gasket.  First place I'd look.  Our x-waterboxer did a similar thing
but for a different reason.  First time, late at nite me and 2 kids headed
to spring skiing in northern Vermont.  70 mph, dark, cold, empty road.
Boing!   coolant lite flashing.  Discover coolant all over the rear of the
van and the engine compartment very wet.  In the end, turned out to be a
failing impeller in the water pump.  Coolant not moving through the system,
stays in the heads and boils like crazy creating huge pressure.  The engine
is overheating, but the temp sensor still says OK since nothing is moving.

Do check for exhaust in the coolant first.  If that's it, fix it quick.  Our
first x-waterboxer had this leak.  Overnite coolant leaked back into the
cylinder.  Went to start it and blam, "water hammer" instantly destroyed
that piston and connecting rod.

Best of luck!!
Gary

----- Original Message -----
From: "Paul Impellizzeri" <pmi@BLUEGRASS.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, December 20, 2001 8:40 PM
Subject: extremely high coolant pressure

> I got a quick question.  I have been having problems with hoses rupturing
> and most recently the end blowing out of the big plastic tee on the right
> hand side of the motor.  I am getting ready to order the replacement tee
and
> want to get all the parts in one order if possible.
>
> Here is what I have going now.  I have gutted the thermostat so it is
> running wide open.  It was bad and had to cut it out on the side of the
> expressway...wasn't opening up.
>
> I am thinking that the problem (aside from the thermostat) is the pressure
> cap on the expansion tank not properly keeping the pressure.
>
> Am I on target with this assumption or is there more I should look at.  I
> have already blown 4 hoses and t-stat and a tee fitting and gallons of
> coolant.
>
>   All this just started happening in the last month.  The engine is a
brand
> new 2.1 rebuild from VWoA.  I have 10 month/10,000 flawless miles on it.