Make sure the pressure cap is functioning properly. It has to be able to
hold the system under pressure. After that you have the classic symptoms of
combustion gasses getting into the cooling system.   The usual causes are
loose heads/failed internal gaskets or a cracked head. You need to make sure
that coolant isn't leaking back into the cylinders. Even small amounts of
coolant getting into the cylinders and then the oil will do damage.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Richard Golen
Sent: Monday, September 09, 2013 7:18 AM
To: vanagon@GERRY.VANAGON.COM
Subject: A Different Coolant Problem

Dear List Members,

Here's a coolant problem for you to ponder. Recently, on my 87 Westy, after
being driven on the highway for an hour or more, the overflow tank gets
completely filled. Sometimes, the coolant level is so high that coolant
sprays from the vent hole on the top of the tank.

The tank slowly goes back to normal level if the van sits for a day or so,
or if I let it idle for a while after the engine is cooled down.

While driving, the temp gauge is in its normal position. I've also bled the
system a couple of times using a "bong".

Any ideas as to what could be causing this?

Thanks in advance.

Ric
Sent from my iPad