I had a similar problem with mine.... temperature gauge would shoot up after 10 minutes of driving and all the coolant would be gone... started watching the tail after replacing the coolant and saw white smoke... found out later it was a crack in the cylinder and it was burning coolant... this may not be your problem, but it mite help...
If the reservoir keeps losing fluid.
The fluid that keeps the body cool is sweat.
A radiator has no moving parts. It's only job is to dissipate the heat of combustion in your engine. If it doesn't do that job, it's bad. One of the most insidious faults a radiator can have is rust and corrosion build up inside the radiator. This keeps the fluid from circulating. Many times, this cannot be seen. A corroded radiator is a bad radiator. A leaky radiator is a bad radiator; it can't hold the fluid. A radiator with a majority of the cooling fins bent so that air can't pass through is a bad radiator; it can't cool the fluid. One of the tests they do on radiators is to pump them up with air and listen for whistling leaks. Sometimes, they submerge them in a bath to see if any bubbles form, and if they form, where they're coming from. If bubbles do form, it is a bad radiator.
Coelom
Not sure if these have one but it could be a bad thermostat.
You may have a bad radiator cap.
Oil is not a coolant, it is a lubricant, but it keeps the engine lubricated to prevent friction, which reduces heat and makes is run cooler. Water in the radiator, and the radiator fan, is what keeps the engine cool.
Scrap it!
It could be the voltage regulator.
If it's a fluid filled hub, yes.
drinking fluid is good for you because it keeps your body hydrated.
Antifreeze keeps your coolant from freezing. It keeps your coolant more "fluid".