Oil is the lifeblood of your vehicle’s engine. It lubricates moving parts, helps keep the engine cooler, inhibits rust and corrosion, and reduces wear.
Without oil, an engine will only run for a few minutes before suffering damage.
“There are different grades of oil for different applications,” says Tony Fallico, Quality Services and CI Manager for Wakefield Canada.
“The grade also depends on climate. Multi-grade oils are formulated to protect the engine from friction and wear under temperature extremes, such as winter and summer.”
Oils are classified by their viscosity, indicated by numbers. Low numbers indicate thinner oils that will remain fluid in the cold, which provides better protection when the engine is started on icy mornings. Higher numbers are thicker oils that retain their protective properties when hot.
Refineries produce base oils of various viscosities, which are then blended in the correct proportions for each use.
While these blends cover a range of temperatures, their percentage of thinner or thicker oils determines their optimum use.
“The lower the number before the W, which stands for winter, the better the engine protection at start-up in cold climates,” Fallico says.
“The higher the number after the W, the higher its viscosity at engine operating temperature. This can make a lot of difference in protection when you are stuck in traffic on a hot summer day.”
Thinner oil rated at 5W-30 will generally be appropriate for winter use in average climates, while thicker 10W-40 offers better friction protection at higher temperatures.
There are also grade extremes such as 0W for very cold climates or 60 for very hot ones, and heavier-duty blends such as 15W-40 for commercial-duty trucks.
Base oil comes from crude oil, which is distilled into four products according to their boiling points. The lowest grade is asphalt, which does not boil, followed by base oil, diesel and home heating oil, and at the top, gasoline.
The base oils are then further separated by their individual boiling points, which represent the higher and lower viscosity grades.
A bottle of engine oil is about 80 per cent base oil, with the rest made up of various additives including dispersant, detergents, anti-wear agents and antioxidants, all of which help to keep the engine clean and running smoothly.