Engine Oil Basics
Everything you need to know to ensure your vehicle has the right engine oil.
By Wendy Helfenbaum | Illustration by Tom Froese
Motor oil keeps your vehicle’s engine running smoothly by lubricating moving parts and absorbing heat, which reduces wear and tear. It also helps cool, clean, seal and protect the engine against corrosion. Today’s automobiles don’t require as many oil changes or seasonal formulations as in the past, so it’s important to follow the manufacturer’s specifications in your vehicle’s owner’s manual. Brian Rigg from AMA’s fleet operations explains how choosing the right oil can help extend your vehicle’s lifespan. Modern oil for modern needs
“Modern engines use technologies such as turbocharging, start-stop systems and variable-valve timing, all of which usually depend on high-quality synthetic oils that maintain stability under heat and pressure,” says Rigg. “Because of this, oil requirements are more specific than they were in older vehicles.”
Choosing the best engine oil for your vehicle depends on engine type and age, your driving habits and the climate. Start by consulting your owner’s manual to find out the recommended oil type, viscosity and quantity for your make and model. Then talk to your mechanic, who can guide you to the right choices.
“Many drivers believe thicker oil is always better, but today’s engines are built with extremely tight tolerances and rely on the correct viscosity for proper performance and protection.”
Synthetic oil versus conventional oil
Conventional, mineral-based oil is mostly used in older cars. Because it’s less resistant to heat and oxidation, most conventional oils don’t offer the same level of protection and efficiency as synthetic oil. Synthetic oil is made by blending chemically engineered compounds with other raw materials. The key to synthetic oils is the consistent size of the molecules, unlike those in conventional oil, which results in superior lubrication. It is factory recommended for most newer vehicles because it better resists breakdown, flows more effectively in cold weather and protects the engine under high heat.
Another option is a synthetic blend, which combines conventional and synthetic base stocks, providing some of the performance advantages of full synthetic at a lower price point. Always use oil that meets the manufacturer’s specified viscosity and certification requirements, says Rigg. “Many drivers believe thicker oil is always better, but today’s engines are built with extremely tight tolerances and rely on the correct viscosity for proper performance and protection.”
Vehicle manufacturers recommend using multi-grade engine oil — conventional or synthetic — which has two viscosity ratings. This eliminates the need for a thinner oil in winter and a thicker one in summer. Check your owner’s manual or oil-fill cap to find out what your vehicle needs.
When to change your oil Oil changes used to be done every 5,000 km or every three months. While that’s still true if your driving is mostly stop-and-go city commutes, modern engine oils are engineered to go for much longer intervals.
Your car likely needs an oil change if the oil level is low, and certainly well before you hear and feel more engine noise or vibration, or you notice a reduction in your vehicle’s performance or fuel economy. Most newer vehicles also use maintenance-minder systems that calculate oil life based on real driving conditions. Note the sticker placed on your windshield at your last service, and change your oil when you reach the indicated mileage.
One more thing: it’s a myth that darker-looking oil means it needs changing. “Discolouration simply shows the oil is cleaning the engine,” Rigg says.
When you understand your vehicle’s engine oil requirements, you can help keep your engine clean for maximum performance and longevity. If you have any questions, ask a mechanic at any AMA Approved Auto Repair Service shop — they will be more than happy to help you choose the best oil for you. AMA