So, I have just finished up a desmog and carb rebuild by @FJ40Jim (Thanks Jim runs very good) and decide to stretch her legs out today. On our trip the truck never got up to operating temps (hour trip). Would this be the t-stat? I just replaced the t-stat and gasket a couple months back along with a new AISIN Fan clutch. I got the t-stat from NAPA and if I remember correctly it was probably the 180F. Could this be my problem? Also, with this being my first cruiser is it normal for the fan clutch to be kicking on at cruising speeds? The old clutch was shot and would never kick on at highway speeds so I am not sure what normal is for a new fan clutch? Or is it kicking on because of my cooling problem? Thanks for any help!