GoPackGo wrote:
Agree. The last time that happened to me I glanced down at the temp gage and I could actually see it start to decrease after a very few seconds. It happens
fast.
Long ago I read that at normal NON-TOWING highway speeds, the fan isn't even needed in most vehicles because the 60 mph wind blowing thru the radiator is entirely sufficient to cool it.
What I don't understand at all is why GM/FORD/RAM don't use electric fans on their trucks instead of engine driven. It's wasted horsepower when you need it most. And I know all these trucks have HP to burn, but when going up a hill I want every one of them pulling instead of spinning the fan.
Tim
Simple, there is no electric fan system that's cheap and robust enough to actually move as much air as the engine mounted fans in use today to keep up with the number of BTU's modern HD diesels need to disperse. Our transit agency helped pioneer an electric cooling package for our buses, That cooling package which only deals with a radiator and intercooler consists of 8 or 9 fans to provide enough air flow through the radiator and intercooler. Both units are about 4 or 5 inches thick. A transit bus only has about 300 HP and 1,000 lb-ft of torque (Typically a Cummins ISL). And the system at full-bore draws over 100 amps. The alternators we use pump out 400 to 500 amps. At partial load it will intelligently throttle each fan individually depending on which unit needs cooling. Intercooler fans are ran almost constantly depending on ambient temps. Every diesel in a pickup would have to have twin alternators to power a cooling system of similar size. Granted, the transit industry doesn't have the economies of scale as the light duty truck industry, but the cooling system alone costs roughly half the price of a typical compact car. But over the lifespan of a bus and all the fuel it saves, it actually pays for itself and then some.
