Is the pressure cap holding the proper pressure? Do you have the correct mix
of antifreeze? If you running the engine hard to climb a hill, do you let it
idle for a minute or two to let the head temp come down a bit? This
percolation must be cured as it is hazardous to your engines health. The
loss of coolant contact also means you are cooling things un-evenly. Warped
heads and leaky gaskets will result. Also, if you are constantly adding
fresh coolant, the fresh oxygen with this coolant promotes corrosion.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
Of Ken Masuda
Sent: Saturday, September 08, 2001 9:56 PM
To: vanagon@GERRY.VANAGON.COM
Subject: (no subject)

I have a 1990 Vanagon that percolates the coolant when I drive to the Summit
in Los Gatos and turn it off. Ive replaced the thermo fan switch to a  lower
temp
and it helped but still percolates. Anybody have a solution?