How often should I change my car's oil?

Change your oil when your owner's manual says to, which is usually set by an oil life monitor or a mileage interval, and in either case at least once a year. There is no single number that fits every engine. Manufacturers publish their own schedules, and they differ by model, engine and how you drive.

Start with the manual

Look in the owner's manual, or the maintenance booklet that came with the car, for two things: the interval, and whether the car has an oil life monitor. Everything else, including what a shop tells you at the counter, should be checked against that page.

If your car has an oil life monitor

The monitor estimates how long your engine oil will last based on how you use your vehicle.^[1] Honda's version, called Maintenance Minder, says the remaining engine oil life is calculated and displayed as a percentage.^[2] Oil life of 15 to 6 percent means the oil is approaching the end of its service life, and service is due soon.^[2]

GM's wording is firmer: when the "Change Engine Oil Soon" message appears, service is required for the vehicle as soon as possible (within the next 600 miles).^[1] Treat that as a deadline, not a suggestion. Book the change, and afterwards make sure the system is reset, either by the shop or by following the manual.

If your car uses a mileage interval

Without a monitor, the manual gives a mileage figure. One Toyota maintenance supplement, for example, lets owners follow either 5,000-mile or 7,500-mile oil change intervals, depending on your circumstances.^[3] Toyota reserves the 7,500-mile interval for non-turbocharged cars driven under light, non-commercial duty on trips longer than five miles in temperate climates (above freezing and below 90° F); the 5,000-mile interval covers most other driving and all turbocharged models.^[3] Your own manual may give different numbers, and those are the ones to use.

When your driving counts as hard

Manuals usually have a shorter schedule for severe use. Toyota's list of special operating conditions includes:

• Towing a trailer or using a camper or car-top carrier.^[3]
• Repeated short trips of less than five miles in temperatures below freezing.^[3]
• Operating on rough, muddy, or salt-covered roads.^[3]

The same list adds extensive idling or low-speed driving, and unpaved or dusty roads. The supplement also says that turbocharged vehicles driven under these conditions should change their engine oil at 2,500-mile intervals.^[3] If most of your driving matches the list, follow your manual's severe-use schedule. Occasional use does not call for it.

Short trips are the one that surprises people in Virginia, where a daily five-minute run to a station or school in winter is common. A monitor will account for this on its own; a mileage-only schedule will not.

Do not go past a year

Low mileage does not mean the oil lasts forever. GM says that under the best conditions the oil life system might not indicate the need for vehicle service for more than a year, but that the engine oil and filter must be changed at least once a year and the oil life system must be reset.^[1] Honda says the same in its own words: if a Maintenance Minder message does not appear more than 12 months after the display is reset, change the engine oil every year.^[2]

Write the date of each change on a sticker or in your phone. If you drive 3,000 miles a year, the calendar is what sets your schedule.

Use the grade the manual names

Interval and grade go together. The Department of Energy says using the manufacturer's recommended grade of motor oil can improve your gas mileage by 1%–2%.^[4] A longer interval is only safe with the oil the manufacturer specifies, so do not swap grades to save money.

Stop and call a pro if

• The oil light or a low-oil warning comes on. Stop driving and check the level; do not wait for the next scheduled change.
• The oil level keeps dropping between changes. That points to a leak or the engine burning oil, which a shop should look at.
• The oil looks milky, gritty or smells of fuel. Have it checked rather than just changing it.
• You do not know the service history of a used car. Change the oil and filter, then follow the manual from that date.
• The manual and the shop disagree. Ask the shop to show you in the manual why they recommend something shorter.

Getting help in Virginia

If you want to do the job yourself, read how to change your own oil; if you would rather pay for it, see what an oil change costs in Virginia. More car questions are under automotive answers, and you can browse oil change shops.

When it is due, post an oil change job and local shops will quote it.