Wanted to get some other opinions on....2012 Rubi unlim was sitting in garage for a couple of days at temps below 35 deg. and altitude of 8000'. I started engine and let it warm up, then drove for approx 10 minutes. I shut it down, & as I walked in front, I heard a gurgling sound. I noticed it was leaking coolant from the overflow container. I'm thinking either a stuck thermostat or a bad radiator cap. After that event, I added a small amount of HOAT anti-freeze/ distilled water; & it has not leaked or overflowed. I then drove it for another 350 miles down to better weather. Gauge never read hot. Your thoughts please .