Those cold gray November skies should be a warning that winter is well and truly on its way. That means it’s time to whip old Bessy into shape for the approaching siege.

A few precautionary measures should be taken before the cold weather sets in, and a few supplies should be stowed away onboard just in case you wind up spending the night in a snowbank somewhere between Cochrane and Nipigon.

Are your batteries ready for winter?

Of the onboard systems, it’s the electrical system that suffers most in winter, and it’s not necessarily because of the cold.

Cold temperatures slow the chemical reactions between the electrolyte and lead plates inside the battery, reducing the battery’s ability to produce power. A fully charged battery may only produce about half its usual power at freezing temperatures, and as little as a quarter of its power at temperatures around -20°F (-29°C).

Cold weather also thickens engine oil, making the engine more difficult to turn over. Weak batteries may not be able to spin the engine fast enough to start it on a cold winter morning.

Adding to the load on the batteries are the longer periods each day when full lighting is required and the heater fans running. In other words, there’s additional load on the batteries throughout the day, which may limit their ability to charge fully.

There’s also a higher risk of sulfation in cold weather caused by the charge level dropping too low. Lead sulfate crystals build up on the battery plates, permanently reducing their charging capacity and lifespan.

If possible, have your batteries load-tested now before the cold puts them to a different kind of test. It’s cheaper in the long run to replace a weak battery now rather than having it fail out on the road leaving you with a jump start bill – on top of the cost of a new battery.

One weak battery in a pack of four will draw the others down with it. Not only is that weak battery just dead weight, it can also hasten the demise of the remaining three. 

If you need to replace a battery, consider the application. Highway trucks that run inverters when they’re shut down need batteries with high reserve capacities to operate all those electrical extras.

Deep-cycle batteries are great for running hotel loads, but they will forfeit some cold cranking amp (CCA) capacity for starting. In most cases, if your charging system is good and you’re not losing voltage and amperage to bad connections, cold starting with deep-cycle batteries won’t be a problem.

Trucks running locally with many starting cycles each day, should use batteries with high CCA ratings — 900 or better. The mileage you run in a day may be insufficient to replace the charge you draw off the battery with multiple starts and only short hops between them.  

While you’re load testing the cells, remove all the terminal connectors, clean them and cover them with a film or dielectric grease to ward off any corrosion. Tighten them firmly and secure them with the tie-down inside the battery box.

We covered battery maintenance recently. You can ready that story here.

Charging system

Trying to keep up with cold-addled batteries and the generally higher electrical loads in winter adds to the alternator’s workload. There’s not much to check here (it’s a good idea to check alternator output if you have the equipment) except to make sure all the contacts and connection points are clean and the cables in good condition.

Any corrosion (green coloration in the copper wire) will restrict the flow of current from the alternator to the batteries, thus preventing them from charging fully.

Thoroughly clean or replace any damaged or questionable cables during the inspection.

And one final thing here: Check alternator mounting brackets, belts and belt tensioners. Engine vibration often loosens things up allowing the belts to slip on the alternator pulley. This can reduce the alternator output — which is not what you want in winter.

Fuel system

Fuel is a cause for concern in cold weather, but a few simple precautions will prevent problems in most cases.

In very cold temperatures (-25°C and below, really), diesel fuel can start to thicken and become gel-like, a process known as gelling. This happens because diesel contains paraffin wax, which begins to solidify and form crystals when temperatures drop.

At a certain temperature, called the cloud point, small wax crystals form in the diesel. While the fuel is still mostly liquid, it may have a cloudy appearance.

As temperatures drop further, the wax crystals grow and start clumping together, reaching the gel point. At this stage, the fuel becomes too thick to flow freely through the fuel system, particularly through fuel lines and filters. With restricted fuel flow, the engine won’t start or stay running for long.  

Gelling is most likely to occur if the truck sits still over a weekend in really low temperatures — getting cold-soaked. Gelling hardly ever happens out on the road.

The greater threat to cold weather operation is water in the fuel.

Water finds its way into diesel fuel through leaky underground storage tanks, poor fuel transfer practices, and through condensation. The water that’s present in the warm fuel inside the tank condenses when it touches the cold wall of the fuel tank, changing it from water vapor to liquid water.

Like the wax in the case of gelling, water droplets are drawn up the fuel intake pipe in the fuel tank and then exposed to the usually uninsulated fuel lines and fuel filters where it can freeze. The droplets are small, but they will coalesce into a larger mass of ice crystals and clog the lines or the media inside the filter.

The result is the same: the engine is starved for fuel and runs poorly or quits.

There is usually all sorts of crap and contaminants suspended in diesel fuel, from tiny particles of dirt and rust to microbes and algae that grow and multiply in warm fuel in the summertime.

Fuel filters are designed to prevent that muck from reaching and damaging the fuel pump and the injectors. When they clog up, they are just doing their job.

Winter fuel and additives

We noted above that gelling is rare in Canada. That’s because refiners here blend a certain amount of kerosene and certain additives into diesel fuel, beginning in November and running through April. Northern parts of the country get a richer blend than the southern areas. 

Kerosene contains no paraffin, so it will not gel. In fact, jet fuel is mostly kerosene, and it sits in aircraft wing tanks for 10-12 hours or longer at temps as low as -60°C at 40,000 feet.

Winter fuel costs more because of the kerosene and the additives, and fuel economy usually drops off a little because kerosene has a lower energy content than diesel. But that’s preferrable to the alternative. The kerosene blended in with regular diesel lowers the cloud point considerably, giving truckers a bit more margin against cold-weather gelling.

Winter blends of diesel fuel are not common south of the border. Some fuel stations offer No. 1 diesel alongside the No. 2 grade. But it’s usually not cold enough in most areas of the U.S. to worry about. It’s something to consider up on the northern plains, the Dakotas, Wyoming, Montana, etc., especially if a cold snap is in the forecast.

The riskiest scenario is tanking up on summer blend diesel down along the Gulf Coast where it’s cheap, and bee-lining for Fort McMurray, Alta., Prince Rupert, B.C., or Sept Isles, Que., where it gets really, really cold.

It’s good practice in the late fall to let your fuel tanks run really low on some weekend, and then drain the water out of the tank. Given a chance to settle (it’s heavier than diesel), you’ll be able to see it at the bottom of the tank. If the inside of the fuel tank is black in color, you may have an algae problem. Having the fuel tanks professionally cleaned or using a biocide additive to kill the growth is good insurance against fuel filter clogging in the colder weather.

And finally, a word on additives. Anti-gelling additives usually aren’t necessary if you’re running winter-blended diesel. You’re more likely to have problems with ice forming in the fuel lines and fuel filters. There are products that claim to be able to de-ice frozen fuel lines and filters. Consult with your fleet manager or maintenance supervisor for recommendations on which products work the best.

A few final points

• Check the overall conditions of the truck, focusing on health and safety related components like heaters, heater fans, and mirror heaters.
• Install new windshield wiper blades and fill the windshield washer jug with –40°C washer fluid — not the summer blend you’ve been using up to now.
• Check the door and window seals for air leaks. Apply a little antifreeze lube spray in door locks.
• Check the exhaust system for under-cab leaks; you don’t want to be snuffed out by carbon monoxide while sleeping with the engine running.
• Check the engine coolant for freeze point, rust inhibitors, etc., and pressure test the system for leaks. At the same time, tighten all hose clamps and inspect all hoses for serviceability.
• Make sure your tires have a decent amount of tread left. If you need new tires, the beginning of winter is a good time to buy them. Tread wears more slowly in cold weather.
• Check your tire inflation pressure. Tires lose about 2 psi for every 10-degree drop in temperature. You might be running a little low if you last checked them in September. If you inflated to recommended pressure at 20°C in Arizona, by the time you get to Winnipeg in January your tires could be down 10-15 psi.
• Clean the old, dirty grease from the fifth wheel locking mechanism. It’s already a bit stiff with road debris; cold temps will only make it worse, which can cause difficulty coupling and uncoupling.
• Keep the air system in top conditions. You can read our recent story on how to keep your air system from freezing, here.