Reviews of Motorcraft thermostat

Your thermostat is probably stuck open. Replace it with an OEM Motorcraft version, not aftermarket.

I replaced the thermostat from a non-OEM to Motorcraft about a month ago, and the only difference has been the speed at which the dial moves from higher temps to its normal positon.

The Motorcraft thermostat sounds promising though, never have an issue with genuine ford parts.

I used a motorcraft RT-1139 thermostat. Comes with a jiggle valve to help bleed air already installed and cost me 8 bucks. You won’t find any place that says they fit other than some forum posts but they do indeed work, I installed one on my MJ with the only issue being me not refilling the radiator after dumping all the coolant.

I bought a Motorcraft thermostat from the Ford dealer for my Crown Vic and it ran about 20 degrees cold.

I requested they use only Motorcraft thermostat, because I knew there was a part # update. Threw the updated Motorcraft one in and it solved the issue.

Soon as i bought Motorcraft all was normal again

I’ve had a Motorcraft thermostat fail after 100mi on my Ford

Make sure you use the motorcraft thermostat.

Go with the Motorcraft thermostat as it has a rubber seal on the outside edge.