There are only two things you have to do to keep your truck running cool: Move water and move air. Did you think it was more complicated than that? It really isn't. But it's the simple stuff that'll get you, which is why overheating is one of the biggest culprits keeping classic trucks off the road. Actually, the problem isn't overheating; the problem is the inefficient cooling system that's causing your radiator to do the chartreuse spew.
If it's all so simple, why do so many trucks suffer from cooling system woes? We talked to a bunch of experts from the aftermarket to find out what end users-that's us-have been doing wrong, and what they can do to make this the coolest summer ever.
Radiator: Moving The Water
One of the biggest mistakes many people make is not allowing enough room under the hood for an adequate radiator and fan. The radiator that was designed to cool a 50-year-old Flathead isn't going to be up to the job of cooling a modern V-8. Oftentimes, there's isn't a lot of room in earlier trucks to accommodate the appropriate components. At that point, selecting a radiator and fan combo is determined by what will fit, instead of what is needed.
The experts recommend choosing a radiator that will provide the most surface area. Moving air will have a much better chance with a taller, wider radiator with less front-to-back thickness. Trying to move air through a thick multi-core radiator can defeat the purpose. By the time that 90-degree ambient air gets to the center of the deep radiator, that air is going to be almost as hot as the coolant it's trying to cool. Another choice you'll face is in the radiator material: either copper or aluminum. There are technical and practical advantages to both.
Copper/brass radiators were the standard for most stock radiators on older trucks. Most current vehicles are equipped with aluminum radiators, and aluminum also makes up the majority of aftermarket radiators these days. Copper/brass is still available, however. Walker Radiators continues to specialize in copper/brass radiators, and Vern Walker reminded us that copper is a superior conductor compared to aluminum. Aluminum, however, weighs less and is more economical. Hand-fabbed aluminum tanks are generally stronger (and more expensive) than stamped tanks, which have a higher likelihood of thin and thick spots that can speed up fatigue.
Another thing to consider, as explained to us by aluminum radiator manufacturers, is that copper/brass radiators may use lead solder as bond material in the tank and the fins. Lead absorbs and holds heat, which could reduce the radiator's overall cooling capability. Copper advocates respond that the pendulum swings the other way when you consider factors such as fin height. Walker, for example, claims to be unique in the fact that their tubes are spaced every quarter inch as opposed to the half inch to 3/8 inch of some other aluminum competitors. In addition, modern serpentine designs are more efficient than older straight fin designs.
Form over function? How about a little of both? Today's modern radiators, though somewhat similar in appearance, are nothing like the old honeycomb-cored antiques of yesteryear. | 
If you're looking to solve the radiator and fan selection for your truck in one fell swoop, look no further than Flex-a-lite. Their FLEX-A-FIT crossflow aluminum radiators feature internal fins that dissipate heat through larger external fins on the side tanks... | 
...(which also offer a cool look), and offer one of the largest surface areas on the market. Adjustable mounting brackets provide for ease of installation. |