It’s that time of year again, when the sun is out less and the weather is getting colder.  We have had a couple weeks of temperatures hovering around the freezing mark, but with the approach of some colder weather that is here to stay what does that mean for our equipment?  


When you’re out working in the cold, you want to make sure that you’re using the right fluids to protect your equipment, and one of the first things you should look at is the viscosity and pour points of your oils. Typically a thinner or lighter grade oil will flow better in colder weather, and there for provide better protection during start up and operation in that cold weather.  

The time the engine is most vulnerable is during a cold weather start up.  The oil has drained out of the system and cooled off overnight as your truck or dozer has been sitting idle. Then when you fire that engine up, the time it takes the oil pump to circulate the oil back through the system is how long your engine is unprotected.   

Figure 1: Cold Weather Operating Limits 


The pour point of your oil has a lot to do with how fast it can recirculate through your engine. If it is too cold for your oil, it won’t flow properly and the engine can suffer damage while the oil is warming up.  Using synthetic products will help with the cold, as they contain less waxes than conventional products and will have better cold weather operating temperatures and better flow at colder temperatures.  

Figure 2: From Left to Right, Increasing Pour Points 

For example; a conventional 15W-40 typically isn’t recommended for equipment operating below -25°C, where as a full synthetic 5W-40 gives you protection all the way down to -35°C.  For extreme cold temperatures, a full synthetic 0W-40 engine oil can provide protection all the way down to -40°C.  This same type of logic applies to hydraulic fluids as well.  If you are using an anti-wear type hydraulic fluid in the summer, like an AW 32 or AW 46, moving into a premium product, like a High-Viscosity Index 32 or into a lighter oil (HVI 22 or HVI 15) can improve the flow of your hydraulic fluid, providing a smooth response to controls, and better protection to the hydraulic system.  


While you are changing out your oil for winter, it is also the perfect time to take a look at some of the other fluids in your equipment, and make sure they are good shape for the cold weather.  How is your coolant looking? Typically we want to maintain a 50/50 ratio of glycol to water, as this will provide freeze protection down to -37°C in your cooling system. And what about your fuel supply?  Low Sulphur diesel can often need a boost from fuel conditioner in order to prevent gelling up and clogging the fuel filter.  


Ultimately when you are making considerations for winter operating conditions, you should always consult your OEM if you’re unsure on the viscosity requirements. A little bit of time and effort pre-planning your winter change outs can save you a lot of time and money down the road.