Maintenance Q&A

December 2018/January 2019

Paul Abelson


A good winter prep goes beyond coolants, fuels and oils

Q. I had quite a long discussion with a friend over the subject of winterizing. I remember as a kid helping my grandpa and then my dad prepare their trucks for winter. Then in the spring, they’d undo everything they did in the fall.

We’d drop the coolant, flush the engine and put in antifreeze. If it was going to be real cold, we’d go from SAE40 to SAE30 oil. Then we’d give the truck a thorough inspection. I say we don’t need to do that anymore. Today’s coolants last years, not months. Fuels are cleaner. Oils last thousands of miles longer. And anything else is done during normal preventive maintenance. So I say winterizing and summerizing are not special anymore. He says it’s more complicated than that and winterizing is a special preventive maintenance. Who is right?

A. Sorry to tell you, but your friend is right. You’re correct about the coolants, fuels and oils, but a good winter prep goes well beyond them. You need to check all your electrics and electronics, your tires and your air system in addition to fuel, oil and coolant. You also need to provide for personal protection.


Even today’s trucks can lose gallons of coolant over a year. And in some service bays, the techs just add water. So you should at least check specific gravity. A refractometer is the most accurate tool. Floating ball types can be way off. If it’s not 50/50 coolant and water, correct it with straight antifreeze. Carry a gallon of 50/50 premix with all the proper additives in it for emergencies. Be sure it’s the right type. There are many variations of extended life and regular glycol coolant. Be sure you have the right formulation.


Wax and water are the culprits. Truck stop fuel is blended for each region, but if you go north, it could get colder than the fuel can handle. A good additive will delay gelling and lower the cold filter plugging point, the temperature at which fuel won’t pass through filters. Additives also clean injectors and control water that can freeze in fuel lines and block flow. I recommend using some at each filling. Follow directions.


Today’s oils are longer lasting and more temperature tolerant than past oils, but they still thicken when cold, as do all hydrocarbon fluids. Use the lowest viscosity allowed in your truck’s owner’s manual – SAE10W-30 or even 5W-50 instead of 15W-40. It won’t hurt engine life, and there will be less starting resistance and internal engine component drag. Synthetics cost more, but the benefits are worth it. Mpg will improve by a percent or two.


Check all exposed wire and connectors for corrosion. Clean with a baking soda solution, flush and allow to dry thoroughly. Protect with dielectric grease, liquid vinyl or heat shrink tube, alone or in combination. Or replace the wire and connector. Heat-sealing connectors cost a bit more but protect much better. Corrosion increases resistance, making batteries work harder. It also messes with electronics.


Today’s trucks all rely on electronics (computers) for everything from engine management to braking and, in the latest trucks, even steering. The computers rely on sensors. Their wires are as important to efficient operations as batteries and lights. Make sure all sensors are functioning. Take a test drive and check gauges. Do a panic stop to make sure the ABS works evenly on all wheels. Check and protect every wire on your truck, or you could face an unexpected system breakdown.

Air system

When you were helping your grandfather, compressed air was limited to brakes and transmissions. Only a few premium trucks had air suspensions or seats. Now, air is used to actuate many critical truck systems. To work properly, the air must be clean and dry. Drain air tanks and leave valves open to allow time for tanks to dry. Check heater connections to prevent frozen valves. If desiccant needs changing, do it now. If you must use deicers (alcohols), do so sparingly to prevent seal damage and valve corrosion.


Check tires for uneven wear and tread depth. Correct any problems. Measure at the point of maximum wear. Although 2/32-inches is legal, you’ll need more for good traction in snow, to drain heavy rain and reduce skidding on ice. During a tire’s useful life, it can wear off as much as 30 pounds of rubber, so the tread depth at the last snow or ice storm will be significantly less than at the first. You should start winter with more than 5/32 on drives and trailers, 7/32 on steers. Don’t forget chains where required. Check their condition.


Winterizing is a good time to check lining depth. If there are any significant differences, you may have system issues that can lead to imbalance. That can initiate a skid, jackknife or trailer swing in an emergency.

Comfort systems

Most APUs and cab heaters are minimal but not zero-maintenance. Small displacement diesels need at least annual service. Belts need checked and changed if worn. Fuel-fired heaters need igniters checked and filters changed. And batteries need to be replaced if weak and their charging systems should be checked. You won’t want an inoperative system on a sub-freezing night.

Personal safety

If you’ll be trucking through snow and ice country (that could include Texas, Tennessee or other points south) there’s a possibility you could be stranded in a storm for hours or even days. Keep a reflective blanket, a supply of water and some instant breakfast bars in the cab for warmth and comfort. (And for reading material, bring some back issues of Land Line.) LL

Paul Abelson, senior technical consultant, is a longtime contributor to Land Line. He’s a member of the Society of Automotive Engineers and a member of the Technology and Maintenance Council. In 1995, TMC awarded him its Silver Spark Plug award. In 2006, he received the Lifetime Achievement Award from the Truck Writers of North America. Although he’s “retired,” he still makes a popular contribution to Land Line readers with “Maintenance Q and A.”