Hi,
Thanks to everyone for your information, suggestions, etc.
I decided to add a "heat spreader" (enhance the heat sink). This particular laptop has a removable panel on the bottom that allows access to the heat sink, fan and CPU. Next to this area is the battery compartment. Since the battery is no good anymore I decided to remove a section between the CPU area and battery compartment. I cut a piece of 1/8" thick aluminum (drilled holes for fan) which I attached to the existing heat sink and supported it at various points. It extends into the battery compartment area.
Now, it takes around 40 minutes before the fan runs, but it doesn't run constantly. It may run for around 10 seconds, then stop. A little while later, same thing.
Brad