I've had my jeep for a little over a year and have gone 500+ miles in it. Just recently I was going up to Bryce canyon and I noticed I was red lining. I pulled off popped the hood to let it cool down. I heard a noise like someone was flicking the hose that runs coolant to the radiator. I waited till it cooled down and when I went forward it started to shoot back up so I reversed to park again and when I reversed it shot back down to normal. It doesn't over heat around town or while it's idling. It gets a little above half when I'm going freeway speeds and it over heats anytime I'm going up the mountain. Or if I am out on a dirt road for a few hours and punch it but it hasn't red lined since? I'm not incredibly wealthy and can't really afford to take it to a shop just to have them do something I could do. Any suggestions?