Date:         Fri, 13 Jul 2001 10:27:01 -0700
Reply-To:     pensioner <al_knoll@PACBELL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         pensioner <al_knoll@PACBELL.NET>
Subject:      Thermostat checking (Overheating)
Content-type: text/plain; charset=iso-8859-1

With that new thermostat, you logically assume it "works".   Once in a
while, when the gods are frowning, you'll get one that almost works.

Wash it with soap and water, put it in a saucepan, fill the pan to cover the
tstat with water and heat it up on the stove/campfire/lava flow.  The tstat
should open before the water boils. (100C at sea level).  You can check the
water temp with a thermometer to determine  1.  When the tstat starts to
open.  2.  When the tstat is fully open.  Note these values and compare with
your expectations.  That silly unmarked guage in the instrument cluster is
PDW.  How hot is "hot"?  How cool is "cool"? That guage isn't going to tell
you.  However, if you install a calibrated guage either degC or degF you'll
know within the accuracy of the guage "hot" and "cool".

PDW same as PDQ with the Q replaced by worthless.  (wuthless for Unca Joel
and Sir Horace).

If the guage indicates "hot" but the radiator fan doesn't come on the hot
coolant isn't getting up to the fan thermoswitch in the radiator housing.

The most common cause of the overheating is radiator blockage.  Either by a
volume of air or by some material in the radiator itself.  You can do a
messy but simple check by unhooking the return line from the radiator,
ensuring that the reservoir is kept full with a water hose and running the
motor without the tstat in the housing.

In spite of some listmembers commentary to the contrary, my opinion of the
vanagon cooling system is that with the WBX pump and the inherent flow
restriction in 20+ feet of piping and tubing it can be "marginal" even with
no air blockage in the radiator.

Didja ever wonder why the Diesel pusher RVs don't mount the radiator in the
front?

Remember, the WBX is an "aircooled" design with a water jacket over the
barrels poorly coupled to the cylinder heads with a waterpump that is at its
design limit even when new.

My 1984 Soob, NEVER overheated in 200Kmi of traipsing around the tri-desert
region.  It was a 1800cc with a much smaller radiator but without the 20
feet of waterway.  Got warm, but never "hot".  I flushed the radiator every
year however.

cheers,

pensioner