Shutting Down the Engine when Radiator Fan is Running?

[arungn]

But This is the same reason by Petrol MPFI enginee is asked to start without leg on peddal?

MPFIs hav ecus which automagically controls rpms to get it to operating temps. Leg on gas only needed for carb cars that too poorly tuned ones

When a car is parked, the engine is already near the idling speed with spurts of power to get it to the required position. This does not generate as much heat as would a car running on a road at a speed

Actually its the other way round. When the engine is idling after reaching optimal temperature/idle-speed the engine makes more temperature since there is no air forced into the block and radiator. Radiator fan switches on more often. A moving car working thru gears at normal rpms runs much cooler and the radiator fan rarely gets activated.

 

[Biddu]

@Arungn,

I agree with you that the radiator fan will not be switching On frequently whilst driving since the moving air is doing the job of the fan. However my point was that the heat generated in the Engine, the surface area required by the radiator to cool the coolant, heat carrying capacity of the coolant, the vapour point of the coolant, the temp at which the bypass to the radiator opens and closes etc etc. all these factors are taken into account at the design stage and the car is manufactured accordingly. Again whilst parking the engine is idling and the fuel injected is low and therefore the heat generated is minimal so the rate of rise in the coolant temp will be minimal leading to a very small rise in temperature (rise which is in the permissible range). Given all the above points, I feel that one need not keep the Radiator fan running.