> my heating system decided to not blow out hot air on the day it is
> into the single digits...the only thing i can think of that i did is
> last week i filled up my antifreeze and after about 1 quart realized
> that i did not dilute it with 50/50 water to antifreeze, so is it
> possible that too much concentrated coolant is doing this...my engine
> heat gauge stays way below cold and does not even creep up after
> driving for an hour

Hmmmm...cooling system doesn't care much what's in it, so long as it's
liquid. The cooling capacity will vary based on the proportion of water to
antifreeze, but not enough to make the heater run cold!
I'd look to the thermostat. A stuck open thermostat in really cold weather
will prevent the coolant from ever heating up. The Vanagon radiator is
really effective, so long as it's not clogged. Sounds like yours is working
VERY well.

--
John Bange
'90 Vanagon - "Geldsauger"