By Paul Abelson, senior technical editor
You wouldn’t go out in a blizzard, or even a snowstorm wearing a light summer windbreaker. You’d dress for the weather with a sweater and warm jacket. Just as you’d prepare ahead and bring season-appropriate clothing with you, you should prepare your truck by providing season-appropriate preparation.
In trucking’s early years, before permanent antifreeze and multi-viscosity oils, preparing for winter was a major undertaking. Radiators were drained and flushed, then refilled with a water and alcohol mix. The alcohol lowered water’s freezing point, but it evaporated easily. It had to be replenished almost nightly. Straight weight SAE 40 oil was replaced with SAE 30 and, before driving to the northern tier of states or depending on the weather, with SAE 20. Before winter set in, heaters and defrosters were checked. Batteries were topped off.
Today, advanced chemistry eliminates the need to change to thinner oil and different coolant types, but preventive maintenance (PM) intervals are still the events that trigger winterizing efforts. Manufacturers’ recommendations for oil drain now run about 25,000 miles. Many operators go longer. But whether at 30,000 or 10,000 miles, the closest PM to the start of cold weather should be when winterizing occurs.
The Technology and Maintenance Council issued Recommended Practice RP311A, Cold Weather Operations. The 13-page document covers all the maintenance and checks to be done to prepare your truck for winter. Here are a few topics covered.
Higher viscosity oils are thicker to provide good lubrication when at operating temperature, but are too thick when cold-starting the engine. That creates drag on engine parts during cold starts, stressing starters and draining batteries. Thinner or lower viscosity oils provide better fuel economy by reducing drag inside the engine. Until now, lower viscosity oils reduced lubrication when engines operated hot.
Choosing the right oil for climate conditions is easier now thanks to developments in synthetic oil technology and better multi-viscosity oils.
Multi-viscosity oils are thin oils with special polymers added. The polymers link together as they warm, thickening the oil. Today’s standard is 15W-40, with flow properties of an SAE 15 when cold and an SAE 40 when hot. Improvements in oil chemistry allowed some 10W-30 oils to perform well in trucks. The latest fully synthetic oils are 5W-50, while for severe Arctic operations, 0W-30 oils are available.
Coolant should be checked for protection from freezing. A 50/50 ethylene glycol (EG)/water mix will protect to minus 34 degrees. If only water has been added over the summer, less protection is provided. At 40 percent EG, the mix will freeze at only minus 12 degrees, well above some of the coldest temperatures encountered. For operations in the sustained cold often encountered up north, a 60 percent EG mix will protect to minus 65.
Coolant should also be checked for additive levels. Conventional coolants need supplemental coolant additives (SCAs) to prevent cavitation and liner pitting, rust and deposit formation, and also to protect solder and non-ferrous metals. If your coolant requires SCAs, measure the concentration with the specific supplier’s test strips. Add more if needed, but be careful not to exceed limits. Too much SCA creates deposits that could abrade surfaces and clog passages.
If you have extended life coolant (ELC), test the freeze point with a refractometer. Coolant three years old or more may need an ELC extender. That can add up to three years of additional coolant life. Follow manufacturer’s recommended amounts when adding extender.
Pure glycol (waterless) coolant should not need service unless some has leaked out of the system or you had to top it off with water in an emergency. Evans, the only supplier of waterless coolant, says if water is the only fluid available, use it to get home. As soon as possible – preferably within two weeks – re-install Evans Heavy Duty Coolant.
The cooling system includes the radiator, heat exchangers, hoses, clamps, control valves, the thermostat and pressure cap.
Gently clean any debris from the radiator assembly with compressed air, pressurized water or steam. Spray from back to front. The assembly includes the charge air cooler, the air conditioner condenser and any oil coolers.
Check the thermostat for proper opening and closing temperatures. Instructions are in the Technology and Maintenance Council’s RP313C, Checklist for Cooling System Maintenance.
Radiator caps maintain pressure in the cooling system to raise the boiling point for a greater safety margin. They rely on a spring to maintain pressure, and springs weaken over time. Parts stores have pressure testers for the caps. Unless you are using waterless coolant, be sure your cap holds at 15 psi.
Check all hoses, including those leading to the heater/defroster and sleeper cab heaters. Excessive hardness indicates oxidation that could lead to cracking. Excessive softness indicates internal degradation that could lead to a hose collapsing. Make sure hose clamps are secure. If you have silicone hoses, make sure you use non-extruding clamps.
The electrical system should get special attention at least twice a year, preferably when winterizing and summerizing. In the spring, you need to remove any corrosion that may have built up over the winter. In the fall, you should take steps to prevent corrosion and to make sure current flow is optimized.
Today’s diesel engines require about 1,800 cold cranking amps (CCAs) to start. CCAs are measured at zero degrees. But trucks often operate in colder climates. The colder it is, the more power is needed, but as temperatures drop, battery output drops too. Starting an engine at minus 20 degrees requires 40 percent more current than at zero, but from zero to minus 20 available current drops 36 percent. That’s one reason to get a margin of safety.
Most trucks come with four batteries, each producing about 650 CCA when new, or about 2,600 amps at zero degrees. There is a trend toward three 875 CCA batteries to save weight. They also produce more than 2,600 amps.
Corroded wires and cables lose some of their ability to carry current, and older alternators may not generate all the current needed to keep batteries topped up. When preparing for winter, check wiring for any signs of corrosion. Coat all cable connections and wire terminals with dielectric grease. Make sure wires going through openings are properly grommeted and no chafing is occurring over metal edges. Be sure fan belts are in good condition and properly tensioned to drive your alternator, and test alternator output.
Vision can quickly degrade with ice or snow on the windshield or mirrors. Check wiring and switches for mirror heaters, and be sure there is sufficient warm air flow through defrosters. When the defroster is on, the air conditioner operates to dry the air preventing condensation on the inside of the glass. Defroster output will not be as hot as heater output.
Winterizing is a good time to change wiper blades. I recommend either rubber-covered winter blades that prevent ice buildup on flex joints or the new one-piece blades with the spring steel internal support and no exposed joints.
Check fuel tanks for water and organic growth. Siphon excessive water, and treat tanks and fuel for slime and water control. When temperatures drop below freezing, water in fuel lines blocks fuel flow and stalls engines. Gelling becomes a problem later in winter.
When winterizing, don’t forget yourself. Make sure you have emergency supplies on hand – warm clothing, an aluminized Mylar blanket, flashlight batteries, high energy foods and drinking water in case you get stranded in a blizzard. LL