The proper method to remove the rear heater core is to block it off or
remove the tees, not loop the hoses together. In fact, looping the hoses
together is detrimental to the front heater operation and can actually
reduce radiator capacity in hot weather. The original set up restricts the
flow of water to the rear heater core. Any water going though that loop is
water not available for the front heater nor the radiator. It is almost as
bad as removing the thermostat to fix an over heating problem.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
dylan friedman
Sent: Saturday, March 31, 2007 2:44 PM
To: vanagon@GERRY.VANAGON.COM
Subject: internal head gasket leak or not?

I fell the need to pass on some positive vibes that I have been
experiencing lately as head gaskets go.
The last three vans that I have been working on, primarily testing and
parting out, all blew bubbles into the overflow tank once they reached
operating temperature.  After pressurizing the coolant system, doing a
leak down and compression test on all three I received differing numbers.
The coolant system test seemed to be what was the constant on the failing
side.  Well, long story short, the rear heater valve and/or the heater
core itself were leaking badly in 2 out of the three.
After disconnecting the rear core and looping the hoses, a quick bleed of
the system and no more bubbles!
These vans are not registered and don't see prolonged highway speeds.
Just wanted to pass this on.

The next time you think the head gaskets are shot, check the rear heater
core and cross your fingers.

dylan