The Vanagon's rear license plate access door is definitely the best place
to introduce the halon.  It'll flood the entire engine compartment
(temporarily - due to it's not being sealed below and the fact that halon's
heavier than air) long enough to extinguish the flames.  Only an object that
has reached an extremely high temp during the fire will attemp to re-ignite
once the halon disperses.  Hopefully you will have gotten it out completely
on the first application.  A small bottle should be sufficient to do the
job.  It is important to have the presence of mind to shut off the engine,
and get everyone out of the van first.  If the key's left on, the engine's
electrical harness may burn through by touching ground, and also the fuel
pump may contimue to deliver gasoline into the engine bay.  Large aircraft
have a "firewall cutoff" T-handle on the instrument panel glareshield that
disconnects all powered electrical wiring and fluid systems (fuel, oil, hyd,
fluid, etc.)with electrical cut-off valves to isolate the engine bay
completely from the rest of the airframe during an engine fire.  Usually,
there's a red light in the center of this handle that glows when a heat
detector (Fenwal rate-compensation type probe) in the engine/ nacelle area
reaches high temp. Also, some even have on board suppression systems (halon)
that would release when the t-handle is pulled, some also have main and
reserve tanks to give two attempts!.  Any of this would be way overkill to
do in a VW van, but would be very cool to have.
  Yes, a strong wind will carry away any fire extinguishing agent, and add
oxygen to the fire.
Aircraft cowling side panels have knock-in fire panels just for the purpose
that you mention, but I believe that the access door is well-suited to the
purpose, if you can reach to open it with getting burned.  Opening the rear
hatch, and then propping up the engine lid would be risky or even impossible
if flames were still present.

HTH,

Mike B.

----- Original Message -----
From: "Loren Busch" <starwagen@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, January 02, 2008 6:27 PM
Subject: Re: Westy OEM fire extinguisher

> Mike, let me stretch the Halon thread and extend it to the Vanagon engine
> compartment.  The worst case scenario in my mind has always been something
> like this.  Driving across a lonely stretch of desert in a constant stiff
> wind.  Smoke appears behind, pull ove, shut down, grab the Halon filled
> extinguisher and head for the back.  Now how to I apply the Halon?  If not
> to hot yet I open the license plate door?  Or drop to the ground and
> squirt
> up into the engine compartment?  And If I'm in a strong wind, will the
> Halon
> just carry away?
>
> The ideal setup in my mind is to create some sort of access port direct
> from
> the outside to the engine compartment, just for sticking the nozzle of the
> extinguisher into in case of an engine compartment fire.  Anyone ever
> though
> that through and figured out how to do it?