Winter preparation is similar to other PMs, so a well-maintained truck should need very little special effort to make it ready. But the entire concept of doing preventive maintenance is to maintain equipment in order to prevent problems from happening. (By the way, you prevent them, you don’t “preventate” them, so the correct term is “preventive,” not “preventative.” I’ve heard many, many dealers, mechanics and drivers pronounce it wrong.)
To prevent problems, you have to first anticipate them, and it’s easy to anticipate there will be cold weather in winter. By understanding how the cold affects trucks, we’ll know what to work on to prevent problems. Let’s look at each system in order: cooling, fuel, air, electrical and finally, you, the driver.
At first thought, it would seem that cold weather would help the cooling system work, not cause problems. After all, we hear about overheating in the summer when the temperature is already high and the air conditioner is adding to the cooling system’s load. But truck engines are designed to operate at temperatures around 195 to 200 degrees Fahrenheit, winter and summer. The thermostat, actually a heat-sensitive valve, increases or decreases coolant flow through the radiator to maintain stable temperatures. The thermostat must operate properly, or your engine will get too cool. Check the opening temperature of the thermostat by placing it in a pot of cold water, then heating the water on the stove. Use a thermometer to observe when the thermostat starts to open and when it is fully open.
Water is one of the best substances known to absorb heat from one object, transport it and release the heat to another object. Heat will always flow from a warmer to a cooler substance. That’s why we use water in cooling systems, even though it creates many problems. Luckily, the problems are easily solved. Water freezes at 32 F, and when it does, it expands and becomes less dense. Ice cubes float in a drink and, as the Titanic’s passengers learned, icebergs float in the ocean. Left to expand inside an engine block, water could generate enough force to crack the block. To prevent this, we mix the water with antifreeze, usually ethylene glycol (EG). A 50/50 mix of EG will lower water’s freeze point to minus 34 F. A 60/40 mix will lower it below minus 50 F. But, surprisingly, a 100 percent concentration of EG will freeze at only minus 5 F. Avoid concentrations greater than 60/40.
Water can cause rusting and contribute to cylinder liner pitting. It carries dissolved minerals that deposit on engine parts to form scale. Scale acts like insulation, making heating and cooling uneven. Special chemicals in coolants, called Supplemental Coolant Additives (SCAs), fight these problems, but too much SCA can precipitate and block coolant flow. Keep SCA levels within limits, usually not less than 3 percent or more than 6 percent. You can check by dipping test strips in the coolant and checking color change against the chart on the package.
Hoses carry coolant. They can degrade, either from internal chemical reaction to coolant chemistry or from heat, chemical and ozone attacks from the air. Hoses with internal damage feel soft and mushy with the engine off. When damage is external, they feel hard and may show signs of cracking.
As engines and radiators cool from operating temperatures to overnight ambient low temperatures (a range of 200 F or more), metal hose fittings expand and contract. If hose clamps cannot compensate for changes in temperature, hoses may leak around the fittings, causing just a bit of coolant loss. But a little loss a day soon adds up to be a lot.
In order to help the engine warm up faster, many drivers use winter fronts over the radiators. A few years ago, engineers thought the best winter-front design was to have an opening in the center, right where the fan was, so it could provide unrestricted flow to the intercooler. We now know that this caused as many problems as it solved due to temperature differences across the radiator. The latest TMC (Technical and Maintenance Council) Recommended Practice calls for uniformly wide openings that run vertically across the entire width of horizontal flow radiators. This new design keeps heat more uniform in the radiator core. The differential expansion caused by the older designs led to numerous radiator and charge-air-cooler failures.
To prepare a cooling system for winter, start with the percentage of antifreeze. Then be sure SCA levels are in range. Check hoses for both internal and external deterioration, and make sure hose clamps adjust for temperature to prevent leaks. Be sure the thermostat operates properly. Thermostats usually fail in the open position, so your engine will take longer to warm up and may run cooler if not under load. If you use a winter front, make sure it meets TMC RP-343 criteria.
Starting problems are often due to fuel, not the engine. When low sulfur fuel was introduced, aromatic content was lowered, too. Aromatic molecules don’t burn as cleanly as other molecules, but they don’t gel as easily, either. Today’s number two diesel, high in paraffinic molecules, can start to gel at temperatures as high as 20 to 30 F. Gelling is more of a problem later in the winter. Starting problems early in the season usually are caused by water in the fuel. You can’t keep all water out. It condenses from the air. Warm, daytime air holds more moisture than cool air. As the tanks and fuel cool, water condenses and flows down the tank walls into the diesel. It enters when you fill on a muggy day or a rainy one. From your tank, it can be carried in small amounts into the fuel lines. When the engine stops, the water, which is heavier than the fuel, collects in low places. If it freezes at a low point in a fuel line, the ice can restrict or even block fuel flow. Without fuel, the engine can’t start. As the air warms up, the ice melts and flow resumes.
Fuel-fired engine heaters like an Espar, Webasto or ProHeat can eliminate cold weather problems by keeping everything warm, including fuel in the tanks, especially when a fuel tank heater is plumbed into the system. (See the article about idling on page 80 of this issue.) Without a heater, you can still treat fuel for water and gelling with chemical additives. Some control water by emulsifying it (breaking each drop into tiny, isolated droplets). Some de-emulsify water, so the fuel cannot suspend it. It flows out of the fuel and remains in the bottom of the tank below the pick-up tube. That way, no water gets into fuel lines. Winter fuel conditioners also treat the wax molecules to delay their forming a gel-like structure. When using fuel treatments, always read and follow label directions. We prefer to stay with the leading brands: FPPF, Howes, Penray or Power Service.
It pays to use a good fuel from a reliable vendor, even if the fuel costs a few cents a gallon more. There are no standards for “winterized” or “premium” diesel fuels, so you must rely on each truckstop’s reputation. If a truckstop cuts corners in housekeeping, they may get water in their fuel storage tanks. Guess where that water will wind up? Amoco used to be the only producer that transported its own diesel and did not use pipeline fuel. Their premium truly was different. Now that they are part of BP, I do not know if this is still true.
Compressed air is extremely useful on a truck. George Westinghouse taught us how to use air to apply brakes when nothing else would stop a railroad locomotive. His invention was later adopted as the only way to generate the forces needed to apply truck brakes. Air, being compressible and elastic, can be quite useful, not just for brakes, but for chassis, seat and cab suspensions, and for loading or unloading devices. But air holds water vapor. When it is compressed, air’s temperature rises and it can suspend even more water. As it cools, the water condenses out of the air, and gathers at the bottoms of air tanks. With the air, water can be drawn through the plumbing into air lines and valves. Water freezes at 32 F, and the ice expands as the temperature drops. If water is not removed from the system, the expanding ice can crack and destroy brake valves. At the least, the ice can form at low spots in the lines and block airflow.
Water removal is important year round, but absolutely essential in winter. The best way is with a desiccant-type air dryer that removes moisture right after the air is compressed. Any free water left in the air will condense in the air tanks. Tanks should be drained after every run.
Alcohol injection is another way to prevent freezing. Just as glycol prevents water in the cooling system from freezing, alcohol lowers the freeze point of water in the air lines. Special injection units are needed to deliver the alcohol. They have reservoirs that can hold methyl alcohol and dispense metered amounts into the compressed air. Of the two systems, air dryers are far more efficient. Following manufacturer’s instructions, you’ll need to replace the desiccant cartridge every one to two years. Desiccant is the substance that dries the air by attracting moisture to its surface.
Air systems use heated valves to blow moisture from the system. Without the heat, the water would freeze. Make sure electrical connections to the heaters are tight and free of corrosion. Use a continuity tester to make sure there is current flowing.
Connections to the valve heaters are just one part of the electrical system. Because so many truck systems are powered by electricity or controlled by electronic devices, care of the power system is essential. Batteries, rated at 80 F, have only 40 percent of their rated power at zero. That’s why the measure of cold cranking amps, or CCA, is so important. At zero degrees and 12 volts, it takes about 1,800 amps to start a big bore diesel. That, by the way, is 21,600 watts. Thankfully, it doesn’t take too long before the engine usually starts. Once running, the alternator should power the electrical needs of the truck and replenish the batteries. When the engine is off, batteries power everything. A set of four 675 CCA batteries will provide up to 2,700 amps of starting power at zero. At 32 F, almost 4,400 amps are available. That’s why an electrical system in good shape lets you run accessories all night with the engine off, and still provides ample starting power.
The secret is to keep the system in good shape. That means cleaning any corrosion from terminals or exposed wiring, and protecting sockets, plugs and connectors with a dielectric compound, like Truck-Lite NYK. If you’ve made any wiring repairs or added accessories, any splices or connectors should be covered with a section of waterproof heat-shrinking tubing or a vinyl liquid made for the purpose. Liquid electrical tape dries to a flexible, yet watertight, seal.
To fully charge the batteries, the alternator, its cables and drive belts must be in top shape. Make sure the belts are in good condition and proper alignment. Check alternator output and make sure it is up to specification. Alternators run at multiple of engine speed, delivering rated power from 1,000 to 1,200 rpm on up to 6,000 rpm. If your alternator output is low at idle but comes up as you rev the engine, you may want to change to a smaller pulley to raise alternator rpm.
The control system
Now we get to the most important system in the truck, its control system. In case you haven’t guessed, that’s you. You have special needs in winter: staying warm, seeing in a snow storm and perhaps having to wait out a storm, stuck in your cab on a stretch of road that’s been closed.
To keep warm, make sure your heater is free of debris and dirt that could affect airflow. Without enough flow, you’ll be cold and your defrosters won’t work. If you have a fuel-fired heater, put in a new fuel filter and make sure the igniter or glow plug is operating properly.
To improve vision in snow, use your fog lights. They should have a flat cut-off so light won’t reflect from snowflakes or fog back into your eyes. Don’t use high beams in snow. The glare will reduce your vision by masking things you’d otherwise see. Be sure your fog lights are adjusted so the cut-off is horizontal. Make sure heater elements in mirrors work as designed. If necessary, change heater grids and clean wiring connectors.
Use rubber covered winter wiper blades or heated blades. They prevent ice build-up that can prevent the blades from flexing and following the curve of the windshield. If your blades are six months old or more, change them. Stiff blades will streak and smear, and will not remove snow or ice. Use an ice-melting washer fluid rather than just the traditional blue fluid. The new yellow, green or orange washer fluids contain glycol and actually do melt thin ice from the windshield. Carry a scraper if you expect heavy icing.
Keep warm clothing on board, including extra dry socks and gloves. Since you never know when you may have to trek through deep snow, keep a pair of boots on hand, too. Your winter survival pack also should include a lightweight, heat reflecting Mylar blanket and survival food rations. You don’t need Army surplus stuff or true survivalists’ foods. We suggest some non-perishable, high-energy foods like granola bars and beef jerky. Candy will help, too, but don’t overdo it. It’s more for morale than for food value. You should carry a variety of canned foods that can be eaten cold. If you do, don’t forget a can opener and some utensils. Water is important, too, unless you want to eat snow. A few gallon jugs or two-liter soda pop bottles full of pure drinking water should get you through most weather emergencies.
We’ve tried to cover the most important steps to take to prepare for winter’s worst, but we know we couldn’t mention everything. We’re always eager to learn, so if you have any winterizing tips of your own, please pass them along. You can e-mail them to me at firstname.lastname@example.org or call Land Line.
Paul Abelson is Land Line’s technical editor and freelances from his office in Lisle, IL.