Air drying high on list for winter prep

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Replacing an air dryer cartridge every fall is a good practice for avoiding problems that stem from excessive moisture in the pneumatic system.Replacing an air dryer cartridge every fall is a good practice for avoiding problems that stem from excessive moisture in the pneumatic system.

For about half the year, the primary function of a truck’s coolant system is to keep engine temperatures down. As cold temperatures move in, the system’s anti-freeze properties become just as important.

A properly maintained coolant system – using the proper type and adhering to the engine maker’s recommended change interval – also has a positive impact on the truck’s heating system.

Cold temperatures also reduce the rate of oil flow and can stress the engine, even to the point of causing it to seize up, said Petro-Canada Lubricants’ Ron LeBlanc. Consequently, standard practice for cold-temperature operation is to use a lower-viscosity oil.

Perhaps less obvious but no less important is winter’s impact on another fluid — water that gets into the truck’s air system. That system’s health can affect brakes and non-braking systems such as automated manual transmissions, advanced driver assistance systems and other safety systems and emissions controls.

Keeping the pneumatic system’s air clean and dry is critical, said Rich Nagel, Bendix’s director of marketing and customer solutions for air charging.

“It’s that ‘dry’ part that becomes even more crucial in lower temperatures,” he said.

When the compressor is charging, moisture in the outside air is drawn in. The air dryer’s job is to prevent that moisture and other contaminants from getting into the system.

“If the dryer fails to do this, moisture can condense inside the air tanks and find its way even deeper into the system,” Nagel said. “This presents problems at any temperature, but when it’s cold out, that condensation can freeze, increasing the odds of malfunctions in brakes and valves throughout the vehicle.”

Annually replacing the air dryer cartridge in the early fall, as temperatures start to drop, is good preventive maintenance, Nagel said. That’s especially true in colder climates or on trucks that use higher volumes of air, such as vocational trucks.

“It is also a good opportunity to inspect the purge valve and heater/ wiring harness, as well as a visual inspection for excess corrosion on the dryer,” he added.

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Bendix recommends using cartridges from the original equipment maker, because some aftermarket products are made with inferior moisture-removing desiccants. Nagel said Bendix also advises using oil-coalescing cartridges, since the oil aerosols passed into the system by the compressor can harm seals and damage other components.