I am going to be changing out the water pump on my 1985 DL (133k) this weekend and figure it would be a good time to try to find the cause of the intermittant screeching that has plagued the car for the last couple of years. I list some facts below and some of the suggestions of what may be causing it. Any other comments/suggestions would be appreciated.

Some facts:
-Mostly occurs in the winter when the temperature is below 45°F
-I applied belt dressing but it didn't help
-Doesn't occur every day.
-Screeches mostly for a few seconds when first starting out but sometimes lasts much longer
-Sometimes helps if the heater fan and lights are turned off but not always
-All belts (including Timing) have about 25,000 miles on them
-Still screeched after I installed new battery 2 years ago

1. Check all belts for tension (they seem OK)
2. Check crank pulley or harmonic balancer for wear/wobble
3. Check water pump (will be replacing this weekend)
4. Check timing belt tensioner

Could the alternator or voltage regulator possibly be the problem?
Could it be the battery (Pep boys) is not up to snuff?