Buick 1993 Roadmaster Owner's Manual page 197

Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly. This:
uses less fuel for the heat that you get and it keeps the
battery charged. You will need a well-charged battery to
restart the vehicle, and possibly for signaling later on
with your headlights. Let the heater run for awhile.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as 'little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Towing, a Trailer
/!\
CAUTION-
If you don't use the correct equipment and drive
properly, you can lose control when you pull a
trailer. For example, if the trailer is too heavy,
I
the brakes may not work well
-
or even at all,
You and your passengers could be seriously'
injured. Pull a trailer only if you have followed
I the steps in this section.