Hey yall, new to me 2018 GMC Sierra z71 with 72k miles. I've noticed since I got it sometimes it'll go above the middle line on the temp gauge. Sometimes it'll go up a little, sometimes more. Doesn't matter if I'm regular driving or flooring it. Doesnt mstter if its 100° or 70° out. Hasn't hit the third line yet but worries me. Haven't even had the truck a week yet. My 2000 Sierra didn't do this, nor does my friends 18 silverado with 100k. But his aero flaps in the front are messed up so I'm not sure if this is normal.