September 19, 2018

Diesel Fleets In Winter

Written by Devon Tamagi


The end of summer is here and as fleets across Canada and the United States prepare for the cold winter months, it’s paramount to keep in mind the health of your vehicle and equipment assets. Diesel vehicles in particular



Diesel vehicles and equipment are great to have for any fleet business. They typically have higher torque, better fuel economy (not to mention that diesel fuel is often cheaper than standard gasoline), and have lower maintenance costs due to increased durability and less parts. Not having parts such as spark plugs means less to maintain, which means a longer lifespan. Diesel engines do have some downsides, for instance while they do have higher torque than their gas-powered counterpart's, they often have less horsepower. Luckily, horsepower isn’t necessary for most fleet vehicles, so that can be disregarded. But the most concerning disadvantage of diesel engines is how they perform in and respond to, cold weather.


If you live in an environment with four seasons, you’ve noticed that your diesel engine doesn’t perform at the same level during late fall and winter. Engines much like anything else, morph depending on the temperature of the surrounding environment, expanding in heat and contracting in cold. All components from the rubber seals all the way to crank shafts and engine block shrink in the cold, then expand again when the engine bay is warm. Since operating temperature is relatively high, all the components of an engine are built with that in mind. Meaning cold temperatures are sub-optimal conditions for performance. Typically, this dip in performance comes in the form of slow starts, bad acceleration and an unresponsive gas pedal. And if the engine isn’t treated well or is left unattended , this could result in serious problems which severely impact the longevity of the asset which hurts your bottom-line. But why does this happen and how can it be prevented?



Most problems related to cold weather and diesel engines are caused by paraffin. Paraffin is a compound naturally found in diesel fuel and is similar in many ways to kerosene (people who live in the UK use the terms interchangeably). Unfortunately when the temperature gets cold enough, paraffin transforms from a liquid to wax crystals. This is called The Cloud Point, when diesel hits this point the wax crystals flow through the fuel lines and coat the filter element. It doesn’t take long for the flow of fuel through the filter to be significantly hindered, which means starving the engine. Typically, a diesel vehicles cloud point is somewhere between –7c and –28c. So what does this mean for your fleet? If the temperature is –7c or below, make sure they are giving their diesel trucks amble time to warm up before operation.

Unfortunately, the Cloud Point isn’t the end of diesel and its problems with cold weather. The Pour Point, is the temperature at which the paraffin has crystallized so much, that the fuel gels and cant flow at all. This usually happens between 5.6c and 11.1c below the cloud point.



Fuel lines run all throughout fleet assets. Meaning it can be difficult to ensure every portion of the vehicle or piece of equipment that has a fuel line, is properly heated. In this case, it is paramount that fleet managers urge their operators to properly inspect assets, ensure that they’re properly warmed up before operation, and diligently maintained. Replacing the fuel filter at an increased rate during winter is advised, especially since most fleet assets are parked outside, unable to secure the warmth of a garage that many personal vehicles benefit from. Additionally, it is wise to ensure your fleet is using high quality diesel, as it’s cloud point will be colder compared to lower quality fuels. If that isn’t enough, you can purchase additives that will greatly reduce the effects of paraffin on your fuel system, keeping it in a liquid state.

But the most effective way of extending the lifespan of your diesel fleet assets, is regular maintenance, which can be challenging for a variety of reasons. Different assets are used at different frequencies and at different intensity levels. That’s why doing maintenance based on a calendar schedule is an inefficient method if you’re concerned about longevity. Instead, consider setting policies where equipment and vehicles are maintained based on engine hours and during the winter months, increase the frequency at which you would replace fuel filters.

Keeping track of all this can be difficult. Luckily, Plug N Track GPS maintenance tracking is at the disposal of all fleet managers who utilize our platform. Keep track of and schedule maintenance based on date or engine hours and by driver or asset. Whatever your fleet tracking needs, Plug N Track GPS has you covered. 



Plug N Track GPS can help keep your diesel fleet running even through the harshest of winters, extending asset life, and saving your business money.