Of all the issues us truck guys are concerned with, engine operating temperature is always at or near the top of the list. Little radiators with big engines, lots of horsepower and lousy air flow, air conditioning, and traffic jams are just a few of the combinations that lend themselves to overheating and the resultant pool of green coolant on the ground.
American Autowire offers a variety of fan controls, their #500800 temperature switch triggers a ground for a fan relay when then engine reaches 195F, it's off at 180F.
One of the methods many opt for to keep an engine below the melting point is an electric fan. And while that often is an effective method of temperature control, something that is frequently ineffective is the control of the fan. We often see a simple toggle switch used, which means the driver has to have one eye on the road and the other on the temperature gauge. More often than not the fan doesn't get activated until the engine is already hotter than it should be, or shut off when it's not necessary.
Another method we frequently see is wiring the fan directly to the ignition switch so it runs whenever the ignition is on; while that method is also simple, it's hardly effective. Besides adding a burden to the oft-overloaded electrical system, the fan runs when it's not needed. And since we all know nothing lasts forever, why wear it out prematurely? Besides, running the fan at highway speeds may actually inhibit airflow, and that's not the point, is it?
Mounted in a cylinder head or intake manifold, the two-wire design allows power-in and power-out to a relay. Their #500399 turns on at 193F, off at 175F.
There are a variety of electric fan controls available that will help take the worry out of overheating. Some are simple with fixed on and off temperatures while others have adjustable on and off points and features like activation when the A/C is turned on and cool-down periods after the engine is shut off.
While we can't show all the electronic fan controls from all those offering them, here are some examples that will help your classic truck keep its cool.
