240 is high...my 2014 with OEM tstat gets to maybe 230 at most if I'm running hard, but always drops to a stable 212-215 running. Does it spike and then return to a lower temp or does it stay high? Mine had gunk built up in the reservoir, and nasty orange crud in the coolant. Did a complete flush which oddly enough, cleared out the gunk, some of which must have been acting like a plug, because it immediatly exposed a leak in my radiator. If you have extended warrenty or low enough miles to still be under factory, I'd have them take a good look at the whole thing including the heating element where it connects to the firewall...had a leak there too. Tell them you smell a sweet burning smell even if you don't. Our model year is notorious for crappy coolant problems...make sure your reservoir tank isn't cracked as well..