How Often Should You Change Your Oil? A Simple Guide

How often should you change your oil?

For most modern cars running full synthetic oil, somewhere between 8,000 and 12,000 kilometres, or roughly once or twice a year, is typical, but the honest answer is that it depends on your car, your oil, and how you drive. The old rule of every 5,000 kilometres is out of date for many vehicles, yet blindly stretching to the longest interval can be a mistake too. Here is how to find the right number for your situation.

Why the old rule changed

The every-5,000-kilometres habit comes from an era of conventional oil and older engines. Oil and engines have both improved a great deal. Modern full synthetic oils last longer and protect better, and many manufacturers now specify intervals far beyond the old rule. So if you are still changing modern synthetic oil every 5,000 kilometres out of habit, you may be spending more than you need to. That said, the right interval is the one your car's maker specifies, not the longest number you have heard.

Start with your owner's manual

The single best source is your owner's manual. It lists the manufacturer's recommended oil change interval and the exact oil specification for your engine. Following it keeps your warranty valid and matches what the engineers who built the car intended. Many modern cars also have an oil life monitor that watches how the car is actually driven and tells you when a change is due, which is more accurate than a fixed number.

The oil type matters

The interval depends heavily on what oil you use. Full synthetic oil lasts the longest and is what most newer cars require. Synthetic blends sit in the middle. Conventional oil, still used in some older engines, needs changing more often. Using the correct specification for your engine matters as much as the interval, so this is not a place to substitute a cheaper grade to save a little.

How you drive changes the answer

This is the part people miss. Manufacturers list a normal interval and a shorter severe-service interval, and a lot of everyday driving counts as severe. Frequent short trips where the engine never fully warms up, stop-and-go traffic, extreme cold, and dusty or salty roads all age oil faster. Our winters and typical city driving push many drivers toward the shorter end of the range rather than the longer one. If your driving looks like that, lean toward more frequent changes.

Time matters, not just distance

Oil degrades with time as well as use, so even a car that covers few kilometres needs its oil changed on a time basis, commonly once a year, even if it has not reached the mileage figure. A low-mileage car sitting through a damp winter still accumulates moisture and contaminants in the oil. So the rule is whichever comes first: the mileage interval or the time interval.

Signs it is overdue

Beyond the schedule, a few signs suggest an oil change is due: an oil change or oil life light on the dash, oil that is very dark and gritty on the dipstick, or a low oil level. Running low on oil, or on old, broken-down oil, is one of the fastest ways to damage an engine, so these are not signs to ignore.

Why not just wait as long as possible

It is tempting to stretch intervals to save money, but oil is cheap and engines are not. Regular oil changes are the single most effective thing you can do to make an engine last, because fresh oil carries away contaminants and keeps everything lubricated and clean. The goal is not the fewest possible changes; it is the right interval for your car, which protects it at the lowest sensible cost.

The bottom line

Check your manual for your car's interval and oil spec, lean shorter if your driving is hard on the car, and change the oil on time even if the mileage is low. Get that right and the oil change quietly does more to extend your engine's life than almost anything else.

Does the brand of oil matter?

What matters most is that the oil meets your engine's required specification and viscosity, both of which are in your manual, rather than the brand on the bottle. Reputable oils that meet the correct standard will protect your engine well. Where people go wrong is using the wrong grade to save a few dollars, or topping up with whatever is on the shelf without checking that it matches. Match the specification, change it on time, and the specific brand becomes a minor detail by comparison.

If you would like your oil changed with the correct oil for your car in Mississauga, our oil change service in Mississauga will use the right specification and check the car over while it is in, with a written quote first. Call FastLane Mechanics at (905) 624-4646.

For where the oil change fits in your overall upkeep, see a simple car maintenance schedule.