10 things to focus on when winterizing your fleet vehicles

Shorter days and those bright, colorful leaves falling off the trees lining Northern U.S. and Canadian roadways are a reminder that winter is coming. If your fleet hasn't already started preparing for the harsh, frigid months ahead, there's little time to waste. Every action taken during autumn to winterize your fleet can save you time and money in January.  

"Preparation before winter is certainly less expensive than a failure on the road," said Tom Stencil, regional sales representative at Eberspaecher, whose career has also included working as a truck driver and a technician. "Drivers want to deliver their loads and not lose time and money. For fleets, the high cost of repairs impacts efficiency and driver satisfaction and leads to poor ratings from customers." 

Luckily, there is still time to prevent weather-related issues from happening by getting equipment ready for winter operations. To help plan, a range of experts weighed in on winterizing best practices for critical systems, what happens if those are not done, and the benefits of being prepared.

Here is an in-depth look at 10 things to focus on when winterizing your fleet vehicles before the mercury plummets to help save your fleet the costs and headaches that winter can deliver:

1. Test battery and electrical health before it gets too cold

"A lot is asked of electrical systems in cold weather," said Daniel Mustafa, director of technical service for TravelCenters of America. "Batteries need to crank over cold engines, and they charge slower. Lights are on longer due to reduced daylight hours, and a battery's freezing point changes when cold temperatures cause water and electrolytes to separate."

To prevent problems, Mustafa recommended avoiding unnecessary battery drain by unplugging cab and sleeper items when they're not needed. He advised that when a truck is parked, make sure load disconnect switches are deactivated. That will allow essential items to function while preventing voltage drops from components that draw power even when unused.

"We recommend testing electrical systems before the weather changes," Mustafa added. "Using tools like an AutoMeter, our technicians can evaluate things like battery cable integrity. That not only predicts the life of the components but also presents an opportunity to prevent a breakdown."

The summer ruins batteries, but the winter brings out the problems, noted Larry Rambeaux, sales application engineer at Purkeys. "If you go into winter without having taken care of things, then you have an increase in jump starts, and if drivers are worried about the truck not starting, idling goes up because they're afraid to shut off the truck," he said. "If you properly maintain batteries before extreme winter cold, you will have improved life and performance for all electrical components."

Rambeaux's advice also included using quality testing equipment for batteries, voltage drops, cranking and charging circuits, and the alternator. He noted that those tests must be done to ensure the entire system is working correctly, and it's essential to maintain and properly calibrate the testing equipment.

Alan Kohler, senior marketing manager at Odyssey, said lead acid batteries often lose some of their operational capacity when subjected to a frigid environment. "A temperature of 0 degrees F, for example, diminishes power by about 30%," he related. "If it's cold enough for the oil to thicken, the battery must expend more energy to start the engine."

Winterizing a heavy-duty vehicle's battery involves inspecting, cleaning, testing, and charging. Kohler recommended the following:

• Check conventional, flooded lead acid battery electrolyte levels, and add distilled water to replenished cells if needed.
• Inspect the case, terminals, cables, and clamps for damage from wear and corrosion. This would appear as a thin, white powder or a blue-green growth. After cleaning, apply dielectric grease, anti-corrosion spray, or petroleum jelly to the terminals.
• Measure Open Circuit Voltage (OCD) and determine the battery's State of Charge (SOC) after it sits for at least six hours and after it has been charged to ensure chemical reactions reach equilibrium and the surface charge is gone.

2. Winterize wire harnesses to keep moisture out

One way to help winterize your wiring is by spec'ing a sealed wire harness, said Andy Summers, director of fleet sales at Phillips Industries. This helps keep out moisture and debris. Failure to do so can result in power drops, leading to flickering, intermittent, or non-working lights, which are both safety hazards on the road and CSA violations.

Aside from regular cleaning and greasing of lighting connections, Summers stressed that keeping the 7-way connections clean at the front of the trailer is vital.

"In regions where deicers are commonly used, more frequent cleaning and the application of dielectric grease on plugs and sockets on both the tractor and trailer are essential to counteract the corrosive effects of these chemicals," Summers said.

Ensuring proper cable support by tightly affixing lights to their pigtail connections and the chassis frame is essential to protect cables from sharp edges or rubbing against the trailer's frame. Summers explained this could compromise the jacketing or cause the cables to become dislodged or damaged.

Regularly maintained mud flaps play a dual role in keeping large road debris like rocks from kicking up and in, creating a barrier against moisture and contaminants that can compromise electrical connections, he said.

Summers warned to take extra care when cutting or splicing sealed harnesses or when pressure washing vehicles, emphasizing the importance of keeping moisture away from couplings such as plugs, sockets, lamp pigtails, and harness connections.

"It's vital to ensure wires are properly seated in terminals for a strong connection, and any repairs should be sealed to keep moisture out and maintain the integrity of the harness," he said. "High-pressure water can force moisture into these components, potentially causing electrical issues or corrosion."

3. Ways to prevent diesel fuel gelling 

Diesel fuel gels when it's cold. In addition to clogging fuel systems, it won't flow or burn. Hot fuel cools when the truck isn't running, and cool outside temperatures cause moisture to collect in the tank, explained Jamie Hagen, owner of Hell Bent Xpress and a former driver. "We use a quality anti-gel additive all winter long and keep our tanks full at night to prevent condensation from occurring," he explained. "Full tanks gather no moisture."

Fuel gelling can also be prevented by using locally purchased fuel in colder areas because it's blended or treated, TA's Mustafa noted. In any of those cases, he recommended removing the fuel and sweeping the tank to remove excess water. The fuel filter should be changed, and the fuel/water separator should be drained.

"Anti-gel additives can pre-treat fuel as well," Mustafa added, "and there are great products like Diesel 911 when you already have a problem."

4. Air systems more vulnerable to winter weather

Rick Conklin, Bendix director of engineering, air supply, and drivetrain, noted that winter conditions increase the vulnerability of air systems. In particular, he recommended the following:

• Drain the air tanks manually at the beginning of the cold weather season to eliminate moisture from warmer months.
• Check the air dryer cartridge. If it hasn't been replaced lately, replacement may be wise before the winter season hits because moisture in the air system can condense and freeze, upping the chances of brake and valve malfunctions.
• Replace the purge valve if you spot corrosion or grit accumulation. Corrosive road chemicals—the kind you'll run into during winter—can damage this valve and cause more significant system issues.

"The largest issue with air systems in winter is water freezing that prevents critical systems from functioning," Mustafa said, "and the easiest way to prevent it is not to let it in. Changing the air dryer filter is a low-cost item that can save a lot of pain. Draining air tanks as part of a pre-trip inspection is also an undervalued procedure."

For Hell Bent Xpress' Hagen, changing air system filters is a standard practice. "We only use high-quality products in this application as cheaper ones have led to issues," he emphasized. "We also purge all of our truck and trailer air tanks."

5. Be sure braking systems are ready for slippery conditions

The importance of brake performance heightens in winter, noted Mark Holley, Bendix director of marketing and customer solutions, wheel-end, so preventive maintenance is imperative before the systems are put to the test and should include the following:

• Check air brake chamber housings for corrosion or damage and ensure dust plugs are correctly installed, which helps prevent corrosive materials from taking hold.
• Regular lubrication on drum-braked wheel ends keeps moisture from building up and enabling corrosion. Also, ensure automatic slack adjusters, clevis pin connections, cam tubes, shafts, and bushings are all greased in preparation for winter.
• Any opening into air disc brake calipers can permit corrosion, so inspect the boots for tears or punctures and check the integrity of the guide pins. Make sure the shear adapter cover is in place and fully seated. Additionally, ensure the pads move freely in the carrier, and check that the brake moves freely on its guidance system.

6. Cooling systems need regional care

Before winter sets in, testing coolant for proper freeze protection is critical, said Brad Jordan, product application specialist at Shell Lubricants. "For most areas of the country, 50/50 antifreeze coolant concentrate/water is sufficient for a freeze point of -34 degrees F or lower. For northern regions that experience extreme cold in wintertime, a 60/40 coolant for -60 degrees F freeze protection should be considered. In all cases, a freeze point check should be done using a calibrated refractometer to ensure adequate protection in cold weather.

"Before winter, you should also check for signs of contamination," Jordan continued. "It's also important to check all hoses, clamps, and connections in the coolant system for cracks or wear, as cold weather can lead to leaks and potential engine overheating. Also, inspect the radiator for blockages, debris, or damage that might hinder proper cooling."

Tommy Smith, regional sales manager southeast, Webasto Thermo & Comfort North America, offered advice about reducing issues with cold engine starts with engine coolant heaters. "When the temperature drops significantly, the oil inside the engine thickens, making it harder for the engine to turn over and circulate the oil," he explained. "Preheating the engine warms up the oil, allowing it to flow more easily and protect vital components."

Starting and idling a cold diesel engine turns it into a soot- and smoke-generating machine that feeds directly into the vehicle's DPF, Jordan noted as well. A combination of un-combusted fuel and particulate matter creates a heavy, wet, and dense coating that forms on the surface of the DPF. The contaminants increase backpressure, significantly reducing engine and DPF efficiency.

7. Engine oil: Low viscosity in winter can benefit year-round

When it comes to cold extremes, high-quality, heavy-duty engine oils offer a world of benefits, stated Darryl Purificati, senior technical advisor, OEM/Automotive for Petro-Canada Lubricants, an HF Sinclair brand.

"Low temperatures affect a lubricant's viscosity, so it can take longer to warm up, and when temperatures drop into the critical zone of the lubricant's operating range, it can thicken or become overly viscous," Purificati explained. "Consequently, if the lubricant flow is severely hindered, it can harm the engine's components, leading to significant unplanned downtime and costly repairs."

Opting for a lubricant with a lower Cold Cranking Viscosity can mitigate these issues by enabling smoother fluid flow during start-up in cold weather, Purificati said. Fleet owners and operators are advised to transition to lower-viscosity oils that maintain flow in low temperatures if they don't already use them.

"Offering better stability and performance across diverse weather conditions, synthetic and synthetic blend oils are also worth considering for winter preparation," Purificati continued. "For exceptionally cold climates, oils with improved low-temperature performance facilitate faster flow during start-up."

Karin Haumann, OEM technical manager, Shell Global Solutions, agreed that low-viscosity engine oil provides several benefits during winter by flowing more readily at cold temperatures, ensuring faster lubrication, and reducing wear on engine components during cold starts.

"An engine that can start quickly in cold weather will also put less stress on the battery and starter," Haumann said. "Low-viscosity engine oils can be used in many diesel engines, but always refer to your vehicle or engine manufacturer's recommendations before switching."

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