Engine temp at 3/4, no heat
 

I'm thinking the thermostat is stuck, is that a good guess? Also, it ran for about 4-5 minutes at 3/4 but didn't go into red, engine should be fine, correct? thanks.

Typically when the thermostat is stuck open the needle will swing between cold/hot on the gauge.

If it's stuck closed it'll run until the coolant in the engine is hot, normally when the tstat would let coolant into the radiator, and then the engine will over heat because the tstat isn't opening.

If your car is going to 3/4 and staying there, something else is probably wrong. The gauge has a big buffer zone, so if it's going higher than the middle the temp really is that hot. Check the coolant level, it's probably low, there could be a leak somewhere.

I recently had the same problem and it ended up being the radiator, it did not have any leaks but apparently it was plugged internally. First check water levels and make sure you bleed the system correctly (plenty on information here in how to do that).

Doe it go to 3/4 at during city driving (stop and go) or high speed highway driving?

Low coolant The heat doesn't work because there is not enough coolant. Do a air bleed on it with heater on.

Follow-up
 

The same scenario was repeated on a 4-mile out and back test (max speed 50 mph, no stop-n-go). The '96 has 230k and I did the cooling system overhaul about 3 yrs ago with a Pelicanparts replacement radiator. I don't have time or place to tinker so off to my mechanic next week...thanks for all the info.:smile: