might be the thermostat stuck shut The radiator and cooling system could be low on coolant
No
Various possibilities including thermostat, low coolant, weak coolant, cylinder head gasket, cylinder head. could aso be your electric fan not working leaking heater core!
The heater will stop getting hot when you're low on coolant. If the coolant is low enough the engine will overheat and it will be severely damaged.
Why would you fix a Chevy Spectrum? lol!
It could, but I'd start by checking the timing. If it's off the car will overheat, and that's easy to adjust. Heater cores are a grade-A pain to replace because you have to take apart the dash to get to them.
Trouble code P0059 means: HO2S Heater Resistance (Bank 2, Sensor 1) The problem is in a heated oxygen sensor
A Fire!
water pump may not be worn out, heater core may be clogging
If the Chevy Celebrity radiator is smaller that the Saturn radiator it might well overheat from not enough cooling capacity. If the Chevy Celebrity radiator is the same size or larger than the Saturn radiator I would think it would not over heat.
Check to make sure the fan clutch is engaging.
Check the air filter.
check your thermostat