Car Overheated with some Strange Behaviour
 

Hi guys, I recently bought a Mazda 6 2007 2.3L manual off my parents, and something strange just happened. I'll give the sequence of events:

- the car passed roadworthy a couple of weeks ago, at which time I presume all fluids were checked for good level.
- a couple of days ago, the lefthand radiator fan broke a fan blade. To keep the car running until I could fix it properly (I was fixing our old car up to sell, and needed the M6 for my daily driver), I removed the fuse to that particular fan. I checked that the other fan still worked, which it did (when the AC was on). My commute is about 10km on a highway, so I assumed the car would be fine so long as I didn't get stuck in traffic. I figured the AC wouldn't be as cold but I could live with that temporarily.
- the wife drove the car in town for maybe 20 minutes, and said it 'smelled hot'. I didn't worry too much about this, because it wasn't very long and I expected that might happen.
- I drove the car to work, AC on the whole time, and towards the end of the highway the temperature gauge started climbing. I checked my OBD2 app and the coolant temperature was about 115°C. I slowed down, and the temperature dropped and stabilised at about 110°C. At the end of the highway were traffic lights. As I pulled up to stop, I turned the AC off (I can't remember why I did this) and the coolant temperature immediately (as in instantaneously) jumped to about 125°C and the car shut itself down.
- I tried to restart the car, and it cranked but wouldn't fire. I popped the hood and there was steam. I left the car where it was and got a lift to work.
- when I returned to the car, I put 5L of coolant into it, and it wasn't full. The car started fine however, and I drove the car the short distance to my parents house with no incidents. The temperature gauge came up to 'normal' range within about 2 minutes of driving.
- there was no white smoke in the exhaust, and the engine ran smoothly.

Some questions:
- do these cars shut themselves down when they sense over-temperature?
- is it feasible to lose 5+ litres of coolant in only one or two overheating incidents?
- would pulling the fan fuse effect anything else in the cooling system?
- is it reasonable that the car would overheat on the highway just because a fan wasn't working? I thought the passive flowthrough would cool the radiator enough.
- does the temperature gauge normally come up to normal range in only a couple of minutes from cold?

The cooling fan is there to cool the radiator and maintain a steady coolant temp of about 95`c. Having no fan will result in overheating.

Also a roadworthy is just that, and inspection of roadworthiness, not a service, not a fluid check.

Thanks, I am familiar with the function of the cooling fan. Also, I thought roadworthys checked for fluid levels but I was mixed up - they check for leaks but not levels.

Un update - the radiator has a hole in it, which explains why it kept loosing coolant and even overheated on the highway. The hole must have happened either from the fan blade breaking off, or from overheating without the fan.