In Reply to: Re: F150 overheat(no more) posted by lonestarjeff on September 30, 2018 at 16:47:04:
I may have told you this before, but I have an outboard motor that did the same thing. The thermostat went bad and after two new replacements it still set off the overheat alarm at normal speeds. It ran fine wide open with no alarm. When I took the tstat out it ran fine with no alarm. New tstat in and alarm. Second new tstat in and still alarm. With no tstat the motor ran fine but would not heat up to normal operating temp. So l drilled a bypass hole in the tstat and bingo, no more alarm and motor still heated up normally.
Replacement parts vary wildly depending on the manuf. Motocraft parts are good. I have had spark plugs with 100k on them.