Date: Tue, 10 Apr 2001 11:40:03 +1000
Reply-To: Jack Newton <johnn@TRIODE.NET.AU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jack Newton <johnn@TRIODE.NET.AU>
Subject: Temperature Gauge - Hot Desert Conditions - LONG
Content-Type: text/plain; charset="iso-8859-1"
After having had the usual Transporter (Vanagon) problems of water leaks and
head replacements, followed by two catastrophic failures of the connections
onto the coolant pipes, resulting in tows home, I am an inveterate
temperature gauge watcher.
Last month I drove across Australia from Sydney to Perth and back doing, in
all, around 9,400 kilometres (around 5,900 miles). Part of the journey
involved crossing and re-crossing the hot and dry Nullarbor Plain - 1200
kilometres (750 miles) of desert with petrol (gas) stations up to 191
kilometres (120 miles) apart. "Lets Go Australia -1998" travel series says
about the Nullarbor - "Only the most self-destructive of outlaws would
drive this route by choice". It is flat, it is long, it is harsh and it is
lonely - so lonely that sections of the road are used by the Royal Flying
Doctor Service as landing strips.
But it is challenge and one hell of a test for a cooling system.
According to Bentley (Section 19.12), the Vanagon (from 1986) cooling fan is
two stage, the first stage cuts in between 89 and 94 C (192-201F) and cuts
out at 81 C (178F) and stage 2 cuts in between 95 and 100 C (203-212F) and
cuts out at 87 C (189F). Bentley (Section 97.200) also shows the radiator
fan cooling switch as operating at 95C first stage and 102C second stage.
My Safari Campervan is air-conditioned, has a two 60 litre (16 US gallon)
water tanks, one cold and one hot (heated by a coil through which coolant
flows).
By way of background, the city driving behaviour of the temperature gauge is
that it normally sits about 1 or 2 needle widths to the right of the LED and
the cooling fan switches on when the needle climbs to 3 or 4 widths past the
LED (usually in traffic jams). After a few minutes with the fan on the
temperature falls and the needle moves to sit just on the LED and the fan
switches off. The needle then climbs back to its normal position.
With the air-conditioning on the needle normally sits over the middle of the
LED as the air-conditioning circuit automatically switches on the cooling
fan. When the valve to heat the hotwater tank is opened, the needle drops
one width to the left of the LED and remains there for a while (as the water
in the tank is heated) before climbing just to the right of the LED. This
gives additional emergency cooling capacity to assist the radiator in
extreme conditions. (Switching on the heater also gives additional cooling
capacity but only the most dire emergency can warrant this punishment on a
hot day!).
On the east -west crossing of the Nullarbor conditions were hot and the air
conditioner was used from time to time. In the interests of fuel
consumption and comfort the speed was a steady 100 kph (63 mph). Such is
the lack of traffic on the Nullarbor that 100kph means that you travel 100
kilometres each hour.
The results were interesting in that the temperature gauge was inconsistent
in its behaviour. With the air con off, most of the time the needle sat a
needle width to the right of the LED and remained there with very little
movement but occasionally it would sit lower almost on the LED; both of
these conditions enabled me to relax. But sometimes the needle would sit
almost three widths to the right of the LED and just stay there hour after
hour without the fan switching on, this caused me concern. At first I
stopped, and checked the coolant level (always OK). Eventually I accepted
that it was either just another idiosyncrasy of the Van or was related to
wind speed, direction and ambient temperature. For instance a relatively
cool headwind would give additional radiator cooling whereas a hotter wind
or a tailwind would reduce radiator cooling. According to Bentley
specifications, the water temperature could reach 94C before the fan
switched on and would come down to 81 C before it switched off. So,
depending on conditions, there is a temperature range of 13 C (23F) that the
radiator can sit in quite comfortably with no problems. This could account
for the needle sitting at different positions from time to time during the
trip. Seems logical to me but has any listee any comments or other
explanations?
On the West to east crossing the weather was cooler and with a good tail
wind I got good mileage and not a scrap of worry from the cooling system
although variations still occurred from day to day.
During the 9,400 kilometres, the Van behaved impeccably. The cooling system
behaved perfectly. No Valium was required.
BTW as well as seeing the temperature gauge, we also saw emus, dingoes, the
odd kangaroo and a lot of quite spectacular scenery.
Jack Newton
Manly, New South Wales, Australia
1989 Transporter Safari Campervan
