OK, it's NOT a Chrysler, but people here are pretty good at solving
problems:

I have a 1989 Mazda 626. It sat in a friend's yard for 2 years, and when I
loused up my Grand Voyager I bought it for $150.

The Anti-Freeze was Rusti-Freeze. It would get up to operating temp when
idling, so I drained the radiator, put in radiator flush and ran the
procedure according to the instructions. I even filled/drained it a THIRD
time to make sure I got out as much gunk as I could.

Refilled it with Peak AF, probably 60/40 mixture since it was going to
freeze that night and didn't want the block freezing. When I took it out
for a ride, the needle hardly moved from Cold. When the car is left idling
for 10-15 minutes, it gets up to operating temp, the guage reflects the
temperature, the fan kicks on, etc.

After two days, I replaced the thermostat, making sure to place the 'plug'
towards the engine side, the same as the old one that came out, and
according to the Haynes manual I got with the car. Still wouldn't get up
to operating temp under normal driving conditions.

Then I replaced the Radiator cap, knowing that sometimes with the
Chryslers this can have an effect on the operating temp. Nada...still
running Cold.

I didn't know how old the timing belt was, so when I replaced the belt I
replaced the water pump also. The old one was leaking, so it has a new WP
and gasket.

STILL Cold!

I can't figure this one out. I have 'burped' the system to try to release
any trapped air; the radiator and the overflow bottle are right where they
should be. It acts like the Thermostat is stuck open; before I go and open
the thing up again, does anybody have an idea or can point out something I
missed?

Thanks!