My 4440 is running warmer this year than it has in the past . The gauge was in the upper part of the white . I took it home and cleaned the ac condenser and the radiator. It t went down a little but it use to run in the green. Installed a new cap. and that helped a little too. The radiator was redone 4 years ago and I put on new heater hoses and new antifreeze this spring. Last summer I had a oil leak and oiled up the radiator and ac condenser bad. I have cleaned it 3 times now using a cleaner that is for aluminum and I have all the oil off. I combed the fins. Could the thermostat be sticking?