On an '83 model, is it normal for your temp guage to go up to 110 before the thermostat opens? When its warming up, it moves way up there, then plummets to 90. (all in the space of a minute or two.) I've read on other posts here that your needle should never cross 105.

Is the thermostat one of those easy-to-replace "Saturn" shaped things, or is it some kind of electronic component?