Thanks to our record breaking summer heatwave, the thermostat on the Jeep had failed in the permanently open position. While we were experiencing 100+ degree days, week after week, it wasn’t noticed because the engine would still come up to temperature. But now that the heat has backed off, my check engine light has been on, throwing a P1281 code (engine too cold for too long). I picked up a new thermostat and gasket a couple weeks ago and finally got time to do the replacement today. As I suspected, once I pulled the housing, the thermostat was locked open. After cleaning up the gasket residue and lining up the new gasket, I bolted everything back together and fired it up. There was one small leak, but a re-torque of the bolts solved it. The engine’s coming up to normal operating temperatures and hopefully the light will go out soon. I don’t have an OBD-II scanner yet, so I’ve got to wait until it goes through enough cycles.