Thanks for the super explanation, Tom.  Never heard it expained so clearly
before.  The veil before my eyes has been lifted and never again will I dare
to shut down my 1.9 L while the fan is running or while the engine is
otherwise overly hot or heated!.

All the best,

Dave Gunning
davidgunning@pivot.net

----- Original Message -----
From: "Tom Boldway" <jboldway@comcast.net>
To: <davidgunning@PIVOT.NET>
Sent: Thursday, May 18, 2006 10:05 PM
Subject: Why wasserboxers leak

Both the 1.9L and 2.1L engines leak due to faulty engineering. Three
problems:
1. The cylinder head rests on two mating surfaces - the steel cylinder
sleeve and the aluminum outer block area which mates around the
circumference of the cylinder head. The aluminum block and steel cylinder
sleeve are not physically connected at all, except at the crankcase area
(end opposite the cylinder heads). Thermal expansion of aluminum and steel
are different - in some situations such as heavy load placed on a very cold
motor the steel sleeves can be crushing the gasket between the sleeve and
head while the gasket between the head and block are almost loose.

2. 4 mounting bolts per cylinder is not enough given the construction of the
heads and block - there's just not enough metal there to prevent some
distortion and warpage.

3. the gasket surface area between the heads and sleeve and heads and block
are not sufficient.

The fourth reason is a mix of engineering problems but mostly operator error
- after a long highway drive where the motor is quite hot - you must NEVER
pull off the freeway to a rest stop and shut off the motor - something
called heat soak will cause the coolant in the heads to boil, increasing the
pressure and popping the hot and weakened head gaskets - most engines in the
front of the car have a coolant hose at the top of the radiator connecting
to the top of the block and another one at the bottom of the radiator
connecting to the bottom of the block - when the water pump is not running
the coolant can still flow through the radiator via convection cooling. On
the vanagon the engine is waaay in the back of the car, the radiator in the
front. This won't happen.
Read your owner's manual - it even tells you never to shut off the engine
after a long drive - you need to idle it for a while before shutting off.

Tom Boldway
Ebay ID: guppybat