At 08:23 AM 3/2/2011, Dave Mcneely wrote:
>so, does that mean that opening the valve to heat  the rear heater
>would be dumb?  It does the same thing -- shunts the coolant from
>the delivery hose through the rear heater to the return hose.

The valve when full open has a crescent-shaped opening with a small
fraction (quick guess would be a fifth) of the area of the inside of
the plastic nipple.  The two situations are not comparable even
without factoring in that the otherwise wasted heat is available at
the turn of a switch.

Incidentally that valve also does not close completely: there's a
tiny channel to allow just enough circulation to keep the coolant in
the heat exchanger from becoming stagnant and attacking the aluminum.

Yrs,
d