I ran the Fiesta ST at a local autocross event a month ago when it started overheating again in 67 degree weather. Immediately after the event, I called Demmer Lincoln and asked to schedule a time for them to look at my car, as their engine tech, Jessica, is apparently the tech for all things Ford hot hatch. She was swamped with work, so the service writer told me to come in next week.
Two weeks ago, I proceeded to drop the Fiesta ST off at the service department. Then… nothing. The car waited and waited in the service queue while several other cars in front of it were undergoing engine replacements or engine work.
Finally, there was a break in the action, and by that, I mean “the service tech had to wait on parts for all of the cars she was working on.” So the Fiesta ST finally rolled into the shop and got a diagnosis.
And the diagnosis is… a bad thermostat. Thermostat replaced, and the car was ready to be picked up. The car spent two weeks sitting outside, only to be buttoned up in an afternoon once it got into the shop.
I do wonder if this thermostat really is the solution to the problem. I suppose I’ll find out at the next autocross. Or perhaps I’ll not bother waiting to find out and just go ahead and replace the car with something else…