Tips to Prevent Cold Starts for Your Fleet

Cold Weather can affect your trucks

Diesel engines are about five times harder to start at 0 degrees F than at 80 degrees F due to thicker oil and the cold weather causing the resistance to movement of internal moving parts. Most people in the transportation industry understand the headaches and complexities cold weather environments have on the diesel engines and their equipment. This article will explain some tips and equipment that helps prevent cold starts.


A basic understanding of how cold weather affects your diesel engine is the metal cylinder walls on the engine become very cold when the temperature drops, so most vehicles are harder to start in cold weather. Because diesel engines require much higher temperatures to fire the fuel, they’ve always been harder to start in cold weather than gasoline-powered vehicles. According to the University of Tennessee, “Diesel’s viscosity increases at lower temperatures, known as “gelling” or “waxing”, eventually to a point where it cannot be pumped and the engine dies–or is unable to start in the first place.” Both of these conditions could cause some downtime for your truck or fleet.


Fortunately, many solutions and equipment help keep your engine warm and your oil flowing. Below are some options to help keep your trucks running and driving down the road.


Engine Block Heaters:

Use glow plugs or block heaters on the engine for cold weather starts. Glow plugs heat the internal combustion chamber area to suitable temperatures for combustion. Otherwise, cold fuel sprayed into the chamber and onto the glow plugs can gel and adhere to these parts. Hard starting and inefficient combustion occur with potential for damage to plugs and cylinder heads. Many diesels come equipped with built-in electric-powered block heaters to keep the engine block warm overnight.


Battery Warmers

If your diesel doesn’t start in cold weather and you remembered to plug in the block heater, your battery may be the reason. writes that “Batteries can lose 35 percent of their power at 32°F and as much as 60 percent at 0°F,” Our previous post wrote about ways to protect your batteries from cold weather conditions and you can read about it by clicking this link. A few products exist to help keep your batteries warm and charged to help prevent cold starts. First, you can use the Artic Fox Battery Warmers which utilize hot engine coolant to provide heat beneath your batteries. Think of this as a blanket for your batteries. Second, you can install a coolant by-pass thermostat which senses the air temperature inside the battery box, and automatically controls the flow of coolant through the Battery Warmer to avoid overheating the batteries. Last, you can utilize an engine start-stop solution, such as Opti-Idle or Idle Smart, that will monitor your battery voltage and automatically restart and run your diesel engine to charge your batteries.


Fuel additives

Using an anti-gelling additive can improve your engine start up in cold weather. This can also improve cold flow by preventing gelling and will even clean deposits from fuel injectors, combustion chambers and intake valves deposits. These additives are fairly well known and can found at any local dealership or service shop.


Jim Minser, Maintenance Manager of 120 tractors at JAT of Fort Wayne, has a detailed checklist to prepare his fleet for the winter weather. Because of their location in Indiana, Jim takes a multi-prong approach to keeping his fleet on the road and out of the shop during this winter. Jim Minser says, “I add 5 gallons of fuel additive for every 7,500 gallons of fuel I receive from my supplier. If the temperature is dropping below 0 degrees F, I will treat the fuel by doubling the fuel additive to provide extra protection as the trucks leave the yard.”  He also leaves a container of Power Service Diesel 9.1.1 in every truck in case the driver gets re-routed to another city without being able to get back to the yard in Indiana.


An important piece of Jim’s cold weather protection is the routine maintenance that his team performs in preparation of winter weather. While his team undertakes routine preventative maintenance on his trucks, they change the fuel filters and fuel separator filters (cost per filter $5-$25) to be sure no moisture has been retained by the filters that might cause problems down the road for the driver. Jim says, “When the engine is hot and the outside temperatures are very cold, moisture may form in the fuel especially if the driver parks the truck for the weekend without topping off the fuel tank before he leaves. If the fuel does begin to gel, it’s quite possible that the fuel gel will end up in the fuel separator.”  Second, JAT of Fort Wayne will change the air brake cartridges to be sure no moisture has entered into these cartridges, which might freeze as the temperature drops below freezing on a cold night. Like most fleets in the midwest, JAT of Fort Wayne are at the mercy of the winter weather conditions but is able to keep their fleet on the road by taking some smart, simple steps to prevent fuel gelling and cold starts.


Cold weather conditions are just the reality of the transportation industry in the United States and learning how to maintain your truck or fleet is important to keep your trucks on the road. The exciting part is that we are a month or two away from Spring and an end to another winter.

About This Author

Ryan is Vice President of Product Development and Marketing at Idle Smart. He holds a BS and MBA from Saint Louis University where he played baseball and was named Academic All-American by ESPN. He currently resides in Kansas City and is a big Kansas City Royals and Chiefs fan.

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