Date:         Mon, 13 Jan 97 22:13:01 EST
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         jag@cs.rochester.edu
Subject:      Diesel temperatures, thermostats and heat.

To the diesel owners worried about their temperature gauge sitting
just over the red LED in the middle. Don't worry, that's about 
90 degrees Celcius, perfectly normal! The unfilled "box" towards
the left (low) end is between 55 and 65 degrees Celcius.

Thermostats come in 80-87 C values. I believe 85 or 87 is what
VW shipped. 

Heat: I used to freeze in my diesel bus. Now I no longer.
Solution: Warmer clothes... Just kidding...

Here are the "mods" that worked for me:

1/ Change to highest recommended temp thermostat (87 C). 7 degrees
warmer water can mean almost 7 degrees warmer air! (and 7C is
12F)

2/ Bleed. Make sure there are absolutely no air bubbles. Even the
slightest air in the system will find its way to the heater core
(the highest point), and dramatically reduce heating. If you hear
"gurgling" noises from the heater core (fan off!) when opening the
water valve (temperature lever), or increasing rpm, you have lots
of air in the system.

3/ Stop cold air leaks.
   a/ There are numerous cables goung through the sheet metal
      under the dash. Make sure all the rubber seals are there and that
      they are actually tight.

   2/ Make sure the "cold only" part of the ventilation system
      doesn't leak. One of the hoses to the side vents had fallen
      out under the dash on my bus. This fall I was wondering why
      I always had a cold draft there...
      Some tape may be neded to seal the hoses/ducts at the junctions.

4/ The old cardbord trick. I dont know how much this really helps,
but I have a cardboard in front of most of both the radiator and
fresh air inlets. Use a type that won't dissovle when wet and be a pain
to clean off the radiator.

Result:

Outside temp -10C (about 15F)
Temp of heated air at outlet: (guess) ca 40-50C 
Inside temp  15 C (about 60F) after 15 min highway driving.
(This is measured in the front though. I have no idea how cold
it is in the back)

Jeffs idea of putting a second heater in the bus sounds good.
Do you plan to put it in the back, as in the late 80's busses?
$25 generic heater core + $10 (??) fan + a little elbow grease =
20 000 Btu more heat. Beats Whipme's $150 aftermarket units.

Misc notes:

1/ Not all thermostats are alike. I posted before about the 4 different
brands I've had various experiences with. I currently use a Wahler
87C thermostat, which does not have the small "leak by" hole normal
thermostats have, and has a strong enough spring to keep shut even
at 3500 rpm and above. (Two of the other brands, stant and motorcraft
were forced open at this rpm and above by the high water pressure).

2/ If you detect, or suspect leaks, see previous post on that subject
for where, what to check.

/Martin '82 diesel westy