thinking on the electrical fan this car has if I remember rite the grand am regal and Oldsmobile all have a thermostatic electric fan. But if the sensor isn't working to tell it to go on it wont. Suggestion make sure with test light that there is current at the fan motor on both sides of sensor.
Check to see if the coolant fan is running. With the engine hot, and running, open the hood and see if the fan is turning. If it's not, then either the fan,temp sensor, relay or wiring is bad.
Check valve in radiator cap malfunction, replace radiator cap.
Levels are probably not fine. Check the radiator not the overfow tank for proper level. The radiator should be full to the top.
The radiator costs about $150 and if you have a shop do it you should expect to pay about 2 hours labor plus coolant. A good estimate would be around $300 to $400 if you have a shop do it. If you do it yourself, around $200.
The lights on your Buick could be out for a number of reasons. It could be blown fuses, faulty wiring, or dead bulbs. Your mechanic would be able to test this.
I would.
my buick century would die but only if i slowed down or stopped after about 3-4 miles....if was a spark sensor? that eventually was replaced?
Usually it is the O2 sensor
Could be anything. Some Autozone stores will run diagnostics for free. Try them if you have one near where you live.
head gasket may need to be replaced
old fuel filter
There are 2 fans that would be running while you are driving and that is normal... the compressor fan if you have the air conditioner running and the radiator fan runs to help keep the radiator cool while the engine is on.