Worry not about a pic, your description is enough.

With the 1989 it is easy to blame the temperature compensation board for this problem, but I think not. The reading is too constant.

Try this: With the temp constant at that little above normal spot, open the windows, turn off the a/c, turn on the air fan to #4, and turn the heat control to max.

This will make the heater core into a mini-radiator, adding a little cooling capacity. If the temp needle drops down, that is an indication that the radiator may be losing cooling capacity due to crudding up (technical term) of some of the lower tubes.

But with such a small problem, I would be watchful but do nothing until it threatens to really overheat.

Good Luck,

Bob

:>)