On Sun, 6 Mar 2005, b.clausen wrote:

> I just bought a 1991 Plymouth Sundance for use as a work car, 2.2 liter
> with a 5 spd. Its got high miles, 161K, but runs real good. I changed
> the thermostat right away cause it was aparrently sticking shut. Now its
> not holding heat very well, any ideas as to why? Kinda stumped

You probably didn't bleed the air out of the cooling system after changing
the thermostat. That's what the threaded plug atop the "water box" is for
(the "water box" being the part of the cylinder head where the upper rad
hose connects, where the thermostat is located). On a '91 with 161K miles,
you may find the plug seized in place, in which case loosen the radiator
cap so it holds no pressure, elevate the front of the car as high as
practicable, and run the engine at a fast idle with the heat on until
normal engine temperature is reached, then for another five minutes or so.
This will allow air to travel to the radiator and out to atmosphere.