How Often Should You Change Your Oil?

The ‘change your oil every 5,000 km’ rule has been repeated so often that many drivers follow it regardless of what oil they use or what their manufacturer actually recommends. Apex Auto Spare Parts explains what oil change intervals actually make sense in 2026.

Where Did the 5,000 km Rule Come From?

This interval dates to an era of conventional mineral oils and looser engine tolerances, when oil broke down faster and contamination accumulated more quickly. Quick-lube chains have also had a financial incentive to recommend frequent changes regardless of oil type — it’s not necessarily based on your specific vehicle’s needs.

Manufacturer-Recommended Intervals (Typical)

‘Severe Service’ — When to Change More Often

Most owner’s manuals list a ‘normal’ and a ‘severe’ service schedule. Severe service applies to:

• Frequent short trips (under 10-15 minutes), especially in cold weather
• Extensive idling or low-speed driving (stop-and-go traffic)
• Towing, hauling heavy loads, or driving with a roof rack/trailer regularly
• Dusty or off-road conditions
• Extreme temperatures (very hot or very cold climates)

If most of your driving falls into these categories — which describes a LOT of Canadian truck use in winter — follow the severe service interval, which is typically shorter than the normal interval.

Why Time Matters as Much as Mileage

Even if you barely drive, oil degrades over time through oxidation and moisture absorption. This is especially relevant for:

• Seasonal vehicles (trucks parked for winter or summer)
• Low-mileage drivers (under 8,000 km/year)
• Vehicles primarily used for very short trips, where the engine never fully reaches operating temperature long enough to evaporate condensation from the oil

Most manufacturers specify a 12-month maximum interval regardless of mileage for exactly this reason.

How to Check Your Oil Condition Between Changes

• Check the dipstick level monthly — top up if low, but don’t overfill
• Dark oil color is NORMAL for synthetic oil and doesn’t by itself indicate it needs changing — synthetic oils contain detergents that suspend contaminants, turning the oil dark while doing their job
• If oil smells strongly of fuel or has a milky appearance, this indicates a problem (fuel dilution or coolant intrusion) and warrants immediate attention regardless of mileage

The Bottom Line

For most modern trucks running full synthetic oil under normal driving conditions, 8,000-12,000 km or 12 months (whichever comes first) is a reasonable interval. If your driving is mostly short trips, towing, or extreme cold, lean toward the shorter end of that range or follow your truck’s severe service schedule.

Frequently Asked Questions