I had a customer in here not too long ago.  His van kept getting hot and
boiling over.  We checked fan speeds, etc, but it just seemed like that he
was not getting a good flow to the radiator.  It would still be not hot (I
have an infrared heat gun to measure this with) when the engine was really
hot.  Basically what we found was that this expansion tank cap was not
holding any pressure.  His tank behind the license plate would fill up and
overflow.  We put a new cap on the expansion tank that held pressure and
bled the coolant system.  Now everything is fine.  The coolant system must
have pressure on it to raise the boiling point of the coolant.  If the
coolant boils then you are going to have vapor lock in the coolant system
and overheat.  Hope this helps.

Thanks,
Ken Wilford
John 3:16
http://www.vanagain.com
http://www.strictlyvwauctions.com
Phone: (856)-327-4936
Fax: (856)-327-2242

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
Of Dan Haydon
Sent: Friday, November 21, 2003 10:03 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Need advice please....

Hi there,

I've posted in the past regarding my 91 GL and how all of the sudden it
began to both heat up quicker than usual and maintain a higher operating
temperature (right above the led light) . So far I've taken it to 2
mechanics and the problem persists. I've replaced the t-stat, checked the
radiator for blockage, and flushed/bled the coolant system. The fan is
working fine too.

The last mechanic said he checked the coolant reservoir for escaped gases
and did not seem to think that this is the problem. I find that hard to
believe though, since I can't think of any other reason why "all of the
sudden" my van heats up quickly and maintains a higher temp. I'm not leaking
coolant and other than this the motor sounds good...

My questions are these: Is it plausible that all of the sudden my temp gauge
would start behaving differently to make it look as if I'm running hotter?
and, does anyone else out there with a newer van experience a quick heat-up,
then operate on the high end of the coolant temp sensor? I've heard that
maybe a new expansion cap fixes things of this nature.....

I am at a loss for what to do and would hate to have to drive the Vanimal
off a cliff....please help!!!

Dan Haydon
Denver, CO