Runs Cool No Matter What

There's some long discussions on TurboFord about thermostats for these engines.  These Lima's do run cool but the temperature gauge is not very accurate.

The stock temperature thermostat is around 192°.  The Stant 45820 SuperStat 192 is the closest to OEM that I found and has been working very well in my car.

During a head gasket replacement in 2013 I decided to also replace hard-to-reach parts, like all the coolant hoses, the exhaust, intake manifold and throttle body gaskets—and the coolant sensor (Ford calls it the Engine Coolant Temperature Sensor—its part # at Advance Auto is WT386P).

Finally the time came for the Test Drive. It was late July here, when the temps are often in the 110-120 range. As I set out one thing became obvious—the tempo gauge was climbing up the dial. Prior to this the gauge showed the coolant temp in the Medium range. I realize that the stock gauges are often inconsistent, but this was a sudden change.

Had I done something whilst changing the gasket? While there was no steam or other indications of overheating, it seemed obvious to me that if I continued I would surely damage the engine. I called my wife, and she followed me back home to make sure I got there—I drove very slowly to minimize any damage.

Once home I changed out the new sensor for an older one. Problem apparently solved, as the needle dropped back to its previous spot in the lower third of the dial, and stayed that way throughout another test drive.

The moral of the story appears to be that while they might appear to be the same externally, there are some sensors that have different calibrations from the others.

I have found that most of these aftermarket parts are inconsistent, I try to grab some of these genuine Ford sensors from cars at the junkyards and keep them in stock.