I've got a question, been thinking about this. There are folks (specifically drag racers, but some corner-carvers too) that install a fan override switch that works even if the car is off. Here's my question: if the car is off, what's the point of running the fan? The engine runs the water pump, which circulates the coolant/water. So, with the engine running, I can see the point of the fan running, especially if the car is parked in the paddock/lot waiting for the next run. But if I turn the car off, and I leave the fan on - the water is not circulating. So the fan is running through coolant/water that's just sitting in the radiator. The water left in the engine block will still be hot. I suppose that if I let the fan run long enough (hours upon hours?) it will eventually cool all the water in the system. I would think, however, that leaving the engine running for a bit *and* the fan on will actually do more then if the car were off (it will also help to cool the oil). UNLESS: if one has an electric water pump that runs after the engine is turned off in conjunction with a fan that also runs, then that totally makes more sense, and is probably better than leaving the engine running. However, 99% of the times I see this, peeps are running a crank-driven water pump. So - do I have it wrong? Is my theory dashed upon the rocks of reality? (FWIW, I do have a fan override switch - but it only works when the car is on, for the reason I discussed above).