Last weekend I drove the car for the first time in about 20 years. I noticed the oil temp gauge doesn't work. Any idea ideas how I can check to see if it's the sensor or the gauge?

Check wire from bottom sender to plug under battery tray. You will find that it is probably open. Sender and gauge rarely go bad.

Will do. Sorry to sound like a total noob but where on the block is the sender so I can follow the wire?

Underside of the motor, near the left-front corner. Pretty close to where the bottom of the dipstick is.

The wire goes across the front of the motor, up through the engine tin on the right, and plugs into a plastic box connector.

The sender is a thermistor, a resistor that changes resistance with temperature. You can unplug the wire from the back of the gauge and check resistance to a ground. If you see "infinite" resistance, something is unplugged. If you see zero, the wire is shorted somewhere. If you see something in the tens or low thousands of ohms, that is pretty normal.

--DD

Awesome. Thanks for the info.