We all know hot trucks are cool. On the other hand, trucks that run hot aren't cool. There's nothing worse than steam coming out from under the hood of your prized pickup while boiling coolant pours onto the ground. Overheating can be an inconvenience or a catastrophe depending on when and where, and to what degree (no pun intended) overheating takes place. But the fact is, with a properly designed cooling system, overheating should not be a problem.
When it comes to engine cooling issues we routinely turn to Don Armstrong of U.S. Radiator. The company has been in business for over 50 years and Don has been there for more than 40 of them. He began as a delivery driver, worked in every facet of the operation, and now owns the place. Today, under his leadership, the company produces over 400 different radiators.
Don has years of experience and does constant research to stay up with the latest cooling system technology, and as he explains it, the core design and not material had the greatest effect on temperature drop. Here's what he has to say on the subject:
"While all radiator cores might look the same, they perform vastly different based on tube spacing and fins per inch. The heat transfer points of a radiator are where temperature is actually allowed to leave the radiator and that occurs where the fins are bonded to the tubes. The more transfer points a radiator has, the greater the temperature drop will be between the inlet and outlet.
"For comparison, a '60s-style core typically had tubes spaced -inch apart; that is -inch of fin between the tubes. By going from a two-row radiator to a four-row core design we were able to double the heat transfer points which resulted in a 15-20-percent increase in temperature drop without changing the other variables such as air or coolant flow.
"U.S. Radiator offers four distinct core designs. The Standard that is found in most OEM-style radiators, the High Efficiency aluminum with 20-percent more heat transfer points, the High Efficiency copper/brass with 20-percent more heat transfer points, and the Optima copper/brass that uses -inch tube spacing with -inch fins that provides 40-percent more heat-transfer points.
"Radiator materials have created quite a bit of controversy. In the '80s, the Japanese came out with a core design in response to the need to downsize radiators and that has become the industry standard because it was efficient enough to allow the re-introduction of aluminum (a less efficient heat-transfer material) at the O.E. level.
"By changing the tube spacing to 38-inch, a core design referred to as High Efficiency in the industry, more tubes or water passages and fins were allowed across the face of a core with a specific width in inches. The design was simple enough, but proved to be very efficient in that more heat transfer points created greater temperature drop inlet to outlet.
"It should be pointed out that the move to aluminum radiator construction was purely financial. The raw materials to build a radiator are purchased by the pound and a finished aluminum radiator weighs about 25-percent of a copper/brass unit (dollars per pound being almost equal at that time). The result was a huge financial savings for car companies.
"When it comes to the difference in performance between copper/brass and aluminum radiators you may find the tests by U.S. Radiator surprising. We found that temperature drops at all operating ranges were virtually the same, with a slight advantage going to the copper/brass unit. But consider this: The thermal conductivity or heat-transfer rate of copper is 92 percent versus aluminum at 49 percent.
"However, the copper fin is bonded to the tubes or water passages using lead solder which is very inefficient and slows the heat transfer rate to just slightly better than that of aluminum. This can be a disadvantage if the bonding process does not allow the copper fin to touch the brass tube and why not all copper/brass cores of similar design, but different manufactures, transfer heat equally.
"Copper/brass radiators, because of their weight and durability, have been around a long time and are easily disassembled and reassembled for cleaning purposes. Not the case with aluminum unless speaking of the O.E. version that comes with crimp-mounted plastic tanks. As a result, the life expectancy of the aftermarket aluminum radiators will be far less than that of copper/brass."
