Few car questions get more conflicting answers. Some people still swear by changing oil every 3,000 miles (about 5,000 km); some modern cars go 10,000 miles (16,000 km) or more between changes. Both can be right, for different cars and different driving. Here’s how to work out what your car needs.
What oil actually does
Engine oil lubricates moving parts, carries heat away, keeps dirt and combustion by-products suspended so they don’t settle as sludge, and protects against corrosion. Over time the additives that do that work get used up, and the oil picks up fuel, moisture and fine particles. Changing it resets all of that.
Start with the owner’s manual
Your manufacturer designed the engine and tested it with specific oils and intervals, so the maintenance schedule in your owner’s manual is the right starting point. It will usually give:
- A distance interval and a time interval (for example, “every X km or 12 months, whichever comes first”).
- The oil specification and viscosity (such as 0W-20 or 5W-30) and any approval standard the oil must meet.
- A separate, shorter schedule for severe or special operating conditions.
The time limit matters even if you barely drive. Oil degrades and absorbs moisture sitting in the engine, so a car that does 3,000 km a year still needs a change at the time interval.
If your car has an oil-life monitor
Many newer cars calculate oil life from engine revolutions, temperature, trip length and other data, then show a percentage or a “service due” message. These systems are generally reliable and already adjust for how you drive. Follow the monitor, but still respect the maximum time interval in the manual, and reset the monitor after every change (or ask the shop to).
Are you a “severe service” driver?
The word sounds dramatic, but a lot of everyday driving qualifies. Manufacturers commonly list:
- Mostly short trips where the engine never fully warms up, especially in cold weather.
- Lots of stop-and-go traffic or long periods of idling.
- Towing, carrying heavy loads or driving in mountains.
- Very dusty or sandy roads.
- Extreme heat or extreme cold.
If that sounds like your week, use the severe-service schedule. It’s usually noticeably shorter, and it’s the one most city drivers should actually follow.
Does synthetic oil change the answer?
Many modern engines require full synthetic oil, and their long intervals assume you use it. Synthetic resists breakdown from heat better and flows better when cold. That said, switching to synthetic doesn’t give you permission to ignore the manufacturer’s interval. Use the oil specification your manual calls for and follow its schedule.
Check the level between changes
All engines use some oil, and some use quite a bit. Running low is far more harmful than running an oil change a little late. About once a month, and before long trips:
- Park on level ground and wait a few minutes after switching off (or follow your manual’s procedure; some cars use an electronic gauge).
- Pull the dipstick, wipe it, push it fully back in and pull it out again.
- The level should sit between the minimum and maximum marks. Top up with the correct oil a little at a time if it’s low. Don’t overfill.
Never ignore an oil pressure warning light. If it comes on while driving, pull over safely and switch off the engine.
Keep the receipts
Keep a record of every oil change: date, distance, and the oil and filter used. It helps with warranty claims, and when you sell, a complete service history is one of the easiest ways to show a buyer the car was looked after.
The short answer
Follow your owner’s manual, or the oil-life monitor if your car has one. Use the severe schedule if your driving fits it. Never exceed the time limit. And check the level monthly. That combination beats any one-size-fits-all mileage rule.
This is general guidance. Your vehicle manufacturer’s maintenance schedule and warranty terms always take priority.
