Overheating Issue 2005 Mini S
 

I was sitting idling the other night after driving for about an hour or so and stopped at a convenience store for fuel and afterwards idled for about 10 minutes and suddenly noticed that my temperature guage needle was spiked and a red light by the needle was on .. I immediately turned off the car, sat their for 10 minutes started it up, needle was where it should be and went home with no needle rising. I did notice I had cold air coming out of the vents when I had the temperature on 76 degrees F. So this morning I noticed that the raadiator resovoir looked a little low and ended up putting 1quart exactly of 50/50 anti freeze in it. Seems like the issue resolved itself. Can being as little as a quart low make a difference on overheating ? Or could there be something more to it. Thx

Normally if it's low there is a leak that caused it to be low