BernieD
Well-known member
Ned said:We downshift to increase RPMs and fan speed to lower the engine temperature. But the mileage does drop under those conditions.
Ned
In your case you are right. Your radiator fan is a direct drive from the engine and is always turning, faster at higher RPMs. For those of us with side radiators, the radiator fan only comes on when the coolant gets above a certain temperature and downshifting doesn't necessarily increase the fan speed. However, the constant shifting between 5th & 6th gears generates additional heat in the engine and transmission, which your downshifting usually overcomes and by downshifting you stop the seeking between gears and reduce the total heat produced.