Thread: Cooling Question
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08-31-2011 11:25 AM #7
Everyone so far has given a good answer so I will throw mine in too....it's a question that will be argued for quite some time to come. When you ask "best", there is an answer.....whichever one does the best job for your situation. A car that idles for hours in heavy traffic at the rod run sometimes takes a different solution than does a car that is primarily driven at high speed on the highway. Similarly, a car driven in Tucson, AZ may take a different setup than would a car driven in Calgary, AB. Air flow over the radiator is the goal. The radiator doesnt care how that happens, it just cares that it happens. An engine-driven fan runs at an rpm proportional to the engine....at engine idle, the mechanical fan is at its lowest speed....if that is sufficient to keep the engine at the desired temperature, so be it. IF the fan were electric, at idle, the fan is turning at its maximium (and constant) speed so it theoretically pulls more air than the mechanical fan (at idle) and therefore, the electric fan is "Better".
At higher speed, either fan needs to shut off and let the natural air flow over the radiator to occur.....that flow is greater than the fan can pull so having NO fan is better at high speed. That's why clutch fans disengage/engage, if the clutch sees low temp air flow that is sufficient to cool the clutch, the clutch releases. When the temp of the air crossing the clutch rises, the clutch engages.....most OEM electric fan systems turn the fan off when the cooling is not needed.
New cars have electric fans for three reasons, cost, control, and packaging. The electric fan is easier to package when the engine is turned sideways or the engine has a bunch of junk hanging on the front. Since everything is sensor driven, the electric fan is easy to start/stop as needed.
Of course, the fan is only a part of the system. Without the proper shrouding, coolant capacity, thermostat, coolant, and system health, the best fan is still a failure.
I believe this was somewhere around 2015, Rick, Rosie and Johnboy
John Norton aka johnboy