Had a really strange thing happen tonight. My dad and I were jumpstarting another persons car tonight with my car (a 2001 Pontiac Grand Am), I was revving at about 1800rpm for 6 or 7 minutes as the battery was really dead (had below 1.5V capacity in it). Then I noticed the temperature gage on my dash slightly creeping above normal. So I turned the heat on to try and cool it down, it didn’t make a difference although it didn’t go any higher than barley past normal. Then we tried to start the other car and it started, so we disconnected the jumper cables from my battery and then shut the car off. Then after about 10 seconds there was steam coming from where the coolant reservoir is, and you could see a bunch of coolant leaking on to the ground, but you couldn’t see where from. Then after just a few second it’s stopped leaking, so we opened the rad cap and a good chunk of coolant was missing, so I topped it up with some extra coolant I had in the trunk and then we drove home 20 minutes on the highway fine with no issues or with it running hot. I haven’t checked yet but it didn’t appear we lost any more coolant. Anyone know what could’ve caused it? Don’t want any future issues as I drive the car pretty regularly. It only has 134,000km on it and it has the 3.4L V6 with a 4 speed automatic transmission.