Date: Wed, 15 May 1996 04:22:58 -0700
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: jwakefield@4dmg.net (john wakefield)
Subject: Re: Wasserboxer cooling (was:Re: aftermarket instrumentation)
Jim Davis wrote (in quotes):
"BTW do you own one of these motors and have first hand experience with
it?" I've owned two spark ignition versions and currently own three of
the diesel versions.
"I don't recall any cooling problems on the list that were tracked to
"design flaw". If it were a design flaw, it would be showing itself in
my vehicle as well - it is not." Safety margin required to accomodate
slightly out of spec systems may not be required on yours, and your
experience may simply be a testimony to you and your atypical vigilance
rather than to the bus cooling system design. What differences did VW
include in later systems like your 87 Syncro compared to those before?
"These are all problems that can and do affect all water cooled
engines. . . Can you site any examples to the contrary?"
Yes, I think any comparison with the great mass of alternative brand
vehicles would easily reveal that water cooled Vanagons have a
disproportionately larger share of heat related problems than others. Do
you honestly think that if this were a Toyota or Honda list that engine
heat concerns would receive much attention? I don't. VW bus failure to
comply with contemporary world standards in this specific area is
reflected in that difference. Already two respondents to your note
indicated that they had to stop and let their systems cool during cross
country mountain climbing. Besides antiques and design defects, what
other class of vehicles typically stopped on those inclines? By
contempary standards, if a typical driver has to nurse-maid their VW bus
along while watching to make sure the heat rejection system doesn't get
beyond prudent temperatures, that's a clear indication that something's
different form the norm.
Then you cite your recent personal experience with your fine running
machine. I'm glad that you have your machine running so well. You say
"I expect that you'll say - "Ahhh, that's only coolant temperature."
No, as a matter of fact, your experience described with your machine
sounds like what all Toyota or Mazda van owners probably expect. I think
if your experience were shared by almost all other owners of VW water
cooled buses, just as with the other brands, this thread would not exist.
Instead, I'll bet there are lots of water cooled Vanagon and Westie
owners on this list whose machines couldn't perform as you described
yours doing.
Jim said "While it would be a bad idea to measure coolant temperature
at the radiator for instrumentation purposes, turning on & off the
radiator fans with a temperature switch here works just as well as a
switch at the engine." Really! So the '83 diesel Westie imprudently
left idling in the hot sun for 20 minutes which never alerted me to the
fact that it was heating by turning on either the low or high speed fan
circuit, but which on returning to the driver's seat was found to have
the heat meter at full scale and the light flashing must have had
defective radiatior mounted fan control thermostat switches, right?
Wrong, I tested both and reported the test a while back in Boiling
Aligators in Florida (having used aligator clip test leads in the water
on the stove). The water in the radiator never got hot enough to call
for the low temp switch to come on at 200 to 208 degrees F. specified in
Bentley. An RV at a camp site should be able to set their idle high to
execute a parked recharge to its battery or batteries, and with an idling
fuel consumption of .13 gallon per hour, the 1.6 VW diesel Westie should
be particularly ideally suited for this. At a pint an hour, that's a
pretty trivial heat load, yet it can't handle it. If you call this
failure to even switch on the low speed radiator fan circuit adequate
design, then I'll accept that you and I have different standards and let
it go at that. Yes it's been front elevated and properly burped. I
guess the changes I'm doing are making it even more adequately able to
reject heat. I've seen a VW diesel motor used in a custom RV generator
that runs for vary long periods at low speed but is connected to the big
bus motor's cooling system, and it was a beautifully running system in
all respects. They said it used so little fuel it wasn't funny and gave
no trouble.
"All VW needed to do is determine the proper engine coolant operating
temperature, and choose a radiator mounted switch with an appropriately
lower setpoint to account for the temperature loss in the hoses between
the engine and the radiator. I believe that they have done this,"
Again we disagree. I'd agree if the water pump/coolant system flow curve
over the motor's operating range maintained a narrow range between the
block temperature and the radiator, but that's just wishful thinking.
"By what calculations have you determined that the coolant lines are
"undersized - for - their - length" ?" Direct observation of differences
obviates the need for calculations. Just as with the famous story about
one of Edison's hired engineeers who he discovered deep in calculations
to determine the volume of a flask, Edison took the flask and filled it
with fluid from a calibrated cylinder and made a direct observation.
Similarly, the diesel Rabbit running the same motor but having short
lines performs very differently when idling or pulling an outrageous
load. Same motor, the only reasonably explicable difference is the
different cooling system.
I'm not going to accept your invitation to engage in personal
comparisons, but in my defence, you described yourself as a kid around
the early 70's when I was working on my post graduate degrees. Could we
stay on the topic of how to make all water cooled VW busses handle heat
as well as yours?
John Wakefield
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