I can't get my fluid coupling fan to turn with resistance when the motor is hot and shut off. Should it trun with resistance when the motor is hot and turned off? The manual doesn't show this test. It says to look for leaks. On my trip I went through 100f temps with AC on full with a full vehicle at 80+ mph. When up steep grades at 4500rpms. The temp guage never moved. I replace the OEM thermostat last year and the rad is a couple years old.