Sunday afternoon from at about the halfway point of a weekly drive 45 minutes from home on the freeway I noticed my thermostat needle jumping up and down. I immediately turned of the a/c and turned on the heater. Turning on the heater helped as the thermostat stayed at lower temperatures. I never reached the red zone until I was on stop and go traffic on the surface street near my home.
The next morning I checked the fluids in my car. All fine except the reservoir fluid was low. i added coolant to the line and went on my way. About four miles down the road my thermostat again began to jump around and stay in the red zone I again turned the heater on but there was no heat and smoke came from my hood. I immediately pulled over safely on the side of a surface street and waited for my engine to cool. This time the reservoir was completely empty and the coolant in my radiator was low. I towed my car home and waited for the engine to cool. I refilled the reservoir and the radiator with fluid. No leaks. I ran the engine for over 15 minutes. No leaks. However, I noticed the fan never came on.
Could this be a leaky reservoir or a broken fan motor? I don’t know how else to troubleshoot.