Most all of the models of aux heaters are made in both diesel and gas --
in fact the gas is the weird one.  In Europe, there are standards as to
how much a car heater has to put out, and the dinky diesels they put in
cars don't cut it.  Thus, Eberspacher diesel-fueled heaters are very common
as stock equipment.

You might try scouring the junkyards for Mercedes diesels with Webasto
aux heaters -- they were factory options and are more common than the VW
diesel heaters.  These are all water-heaters.

So if you hear talk of a BA6 Eberspacher, the diesel version is a DA6 --
"B" stands for "Benzine" the German word for gasoline.  The current Espar
heaters are all named like this.  All these heaters are really expensive.
Espar is getting something like $2000 for them.  They seem to have no interest
in the automobile market -- Espar's main customers are the big diesel
trucks, school buses and the military.

For trucks, it makes more sense to run a water heater than the engine to
keep everything warm.  The school buses usually run air-heaters (like the BA6
was) -- only larger.  Even for gasoline-powered equipment, diesel heaters are
common, as the fuel is *much* safer.  It is worth the extra fuel tank,
sometimes.  Locally, our Espar dealer makes most of his sales to a maker
of self-propelled howitzers.  Apparently, they use Espar heaters to keep
the gun recoil mechanism warm...diesel, of course.

Malcolm