Radiator TLC

| June 01, 2006

Cooling efficiency will drop fast when corrosion blocks a radiator’s tubes.

With aerodynamic styling and hotter-running engines, radiators have to work even harder.

The radiator in today’s truck needs to throw off more heat while occupying less space, resulting in designs that cram more cooling surface into a smaller space and have thinner metal sections. Since these thin sections can be vulnerable to corrosion on both sides, maintenance is more important than ever.

We visited Mike and Daughter Radiator Aid in Lancaster, Pa., to get the low down on just what destroys radiators, what keeps them together and what you should keep in mind when needing a repair. Mike Mascuch started the business in 1960 and eventually sold it to his daughter Shawn Marie Sholly, who is president. Her husband Tom Sholly is vice president.

The business purchases its quality replacement cores and radiators from Proliance and another manufacturer, and Proliance helped us arrange for our visit.

Shawn Sholly told us preventive maintenance can make a big difference in the life of your radiator. She says, “If more people did more preventive maintenance, I’d have fewer radiators to repair.”

How radiators work
Radiator is a misnomer – the unit radiates very little heat. The unit’s purpose is to provide a very large surface to heat the outside air, an ideal means of getting rid of the heat in the coolant.

The radiator has top and bottom header tanks that collect and guide the coolant to and from the engine. The tanks are connected by dozens of very thin metal tubes that are flat on the sides to maximize the number of tubes and amount of surface that can be fitted into a small space. The use of these thin, narrow coolant passages ensures the liquid will flow through the tubes rapidly, rather than becoming stagnant. This increases the unit’s ability to get rid of heat, but makes radiators subject to internal clogging if you don’t keep your coolant in top condition.

Once the thermostat opens, the coolant passes down through the tubes, dropping its temperature 20 degrees or more even on the hottest days – if the radiator is clean both inside and out.

The tubes are linked with hundreds of closely spaced flat metal fins. The fins don’t contain any liquid, but because metal carries heat very effectively and no part of any fin is more than a half-inch from a tube, they get almost as hot as they would be if they were filled with coolant. The result is a lot of hot square footage. A radiator with just 200 fins 20 inches long and 5 inches wide would have 250 square feet of surface to heat air, and that doesn’t even count the coolant tubes themselves.

The rub is that those closely spaced fins catch dirt. They are only .003 inch thick these days, Mascuch says. That’s so thin that fatigue combined with high-speed wind can actually bend them.

So, Masuch told us, it’s really important to keep the radiator clean, both inside and out. Outside cleaning must remove not only road salt, which will corrode the radiator, but non-corrosive dirt that would reduce cooling efficiency. Dirt not only blocks the flow of heat from metal to air, but reduces the amount of air passing through. Air is the only place the heat has to go.

Cooling problems always snowball and attack the radiator. Anything that interferes with the radiator’s ability to get rid of heat increases the operating temperature and pressure in the system. The higher temperature and pressure then accelerate corrosion and physical stress, which work together to create radiator leaks.

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