It works!!!!...... I have made a heater for my 2.0L aircooled camper which
doesn't rely on warm air being puffed all the way from the engine to the
front.
 It uses a home made water heat exchanger mounted on the old air heat
exchanger. This heats water which is electricaly pumped through 0.5 inch
rubber tubing to a conventional car heater matrix and blower from a
breakers yard. I mounted this in the space above the spare wheel and ducted
the warm air produced into the exsisting air input which is under there. OK
the temperature of the output is never going to burn anyone but the fact is
I now have a vehicle with a heater!
 This may seem insignificant to all the watercooled owners but for me it is
a major success story and no more rusted heat exchangers for the M.O.T. man
to fail me on.

Martin Laycock
'82 Camper
Glasgow
Scotland