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Cooling Your Engine [/h] by
The Mechanic Next Door

There’s one sure-fire way to ruin your day, engine, reputation under the hood, and road trip this summer. It’s fast, requires virtually no effort or planning, and happens to countless drivers every day. All you have to do is let your engine overheat because of insufficient cooling.
In this instance, I’m not talking about the more common, run-of-the-mill catastrophes usually behind a cooling system failure, including broken hoses or belts, insufficient coolant level, water pump or thermostat failure, or foreign object piercing the radiator.
Less dramatic, but equally effective at causing an engine to overheat, are scenarios in which a vehicle’s cooling system can’t dissipate enough heat fast enough to prevent an overheated engine. In most cases, it’s the result of an efficiency issue, even when everything on the cooling system is working properly. In other situations, modifications designed to coax more horsepower from the engine might also require changes to the cooling system because more horsepower usually equates to more heat generated.
Here’s a look at several add-on solutions to prevent engine overheating.
Performance radiator
There’s a reason copper and brass have historically been materials of choice in vehicle radiators. Copper is great when it comes to thermal conductivity, performing 50 percent better than radiator fins made from aluminum. And brass is durable. So why are
aluminum radiators becoming all the rage in high-performance engines and even among vehicle manufacturers? Weight. Aluminum radiators weigh 10 to 15 pounds less than traditional radiators. And they compensate for the reduction in their material’s thermal conductivity with increased radiator surface area and coolant capacity, design, fin spacing and even tube size.
The larger the radiator’s surface area translates to greater airflow reaching more coolant which means improved cooling capability. The limiting factor here is the amount of space you have or can create in which to shoehorn in a larger radiator.

Most radiators utilize a single-pass design – hot coolant comes in one side of the radiator, passes through, and exits out the opposite side. For increased cooling capacity, look at a dual-pass, horizontal-flow radiator. With this design, coolant passes through one half of the radiator, but instead of exiting, it then passes through the other half of the radiator, essentially making two passes instead of one.
Moving to a dual-pass radiator will probably also require a water pump upgrade because this radiator design places more demand on the pump. Which brings us to the topic of coolant speed. An aluminum radiator with larger diameter tubes is going to require an increase in the speed at which the water pump is moving coolant through the system. Your muscle car’s pulley-pump speed might have been sufficient when everything was stock from the factory, but any modifications made might now require changes to that speed and ratio.
In addition to tube size, high-performance aluminum radiators also have more fins, spaced closer together, for increased heat transfer from the coolant to the atmosphere.