I have a 2015 JKU that the engine temp constantly runs 245+ At highway speeds. Before this the Jeep had a bad thermostat that has been replaced twice now. The increase in coolant temp started after the replacement. I have also had the radiator replaced with an OEM replacement and a new engine dropped in and still running close to 250. I have not boiled over yet and I definitely don’t want to. This engine is a 3.6 liter V6. In order to bring the temps down I turn on the heater full blast. City streets the Jeep runs at 222-240 with A/C on. I did check my fan clutch and the fan spins with no resistance when off and engine cold. Any thoughts? I’m a little frustrated at this point. Jeep has a winch and aftermarket bumper. Mechanic removed winch and bumper to test and found no change in temps.