Good signs, Nando. Hopefully it was just a stuck-closed thermostat or bad sensor, but keep an eye on it and shut it down quickly at any sign of an overheat. Keep checking the coolant for bubbles as the engine is running with the cap off (let it warm up so the coolant is flowing, but DON'T take the cap off then...leave it off until the engine warms up...just in case you didn't know). Keep an eye on the oil for any foam.

And forget about the Sunfire engine. Not even worth considering.

John B.