I inherited the car with overheating issues, I.

I inherited the car with overheating issues, I was told the radiator and distributor need to be replaced but I pulled the distributor and it looks brand new once I pulled off the cap so I put it back on and the car still starts. I let it run for 5 min but the top hose stays cold and no hoses I can reach and grab get warm. I also noticed that the radiator fan(the one on the left side when you are looking from the hood, or the one of the passenger side) is not spinning. There is significant corrosion around the passenger side of the radiator on the top. What could be causing the fan not to tun on? Is it a bad sensor( I replaced the thermostat) could it be a fuse? The liquid in the coolant resevour looks very clear like water.