Check your oil every month, or before any long drive
The simplest rule: check your engine oil once a month and again before you take a trip longer than a few hours. Most cars lose oil gradually through normal wear, and catching a low level before it becomes a problem prevents engine damage that costs thousands to repair. A monthly check takes five minutes and costs nothing.
If your car is newer (made after 2010), the engine is designed to use less oil between services, so you may find the level stays stable for months. Older cars, cars with higher mileage, or cars that burn oil tend to drop a quart or more between oil changes. The only way to know which category your car falls into is to check.
Some drivers check every time they fill the gas tank. Others check every other fill-up. The middle ground—once a month plus before long drives—catches problems without becoming a chore you'll skip.
Key Takeaways
- Check your oil at least once a month, and always before driving more than a few hours away from home.
- A low oil level can cause engine damage within days or weeks, so catching it early prevents expensive repairs.
- The check itself takes five minutes: park on level ground, wait a few minutes after the engine cools, pull the dipstick, wipe it, reinsert it fully, and read the level.
- If the oil is low, add the type specified in your owner's manual—mixing types or using the wrong grade can harm the engine.
- If your oil level drops more than a quart between oil changes, have a mechanic check for leaks or internal wear.
Why the oil level matters more than you might think
Engine oil does three critical jobs: it lubricates moving parts, carries away heat, and keeps dirt suspended so it doesn't scratch the engine. When the oil level drops below the minimum mark on the dipstick, the oil pump can't pull enough oil to do all three jobs at once. The engine runs hotter, friction increases, and metal parts begin to wear faster.
Driving on low oil for even a few days can cause permanent damage. A bearing can seize, a piston ring can crack, or the engine can overheat and warp. Once that happens, the engine either needs a complete rebuild or replacement—a bill that often exceeds $3,000 to $5,000. A quart of oil costs $5 to $10.
The risk is highest in summer heat, in stop-and-go city driving, or if you tow a trailer. All three put extra stress on the engine and make it burn through oil faster. If you do any of these regularly, check more often than once a month.
How to check your oil correctly
Park your car on level ground and let the engine cool for at least five minutes after you turn it off. Oil expands when hot, so a reading taken while the engine is warm will show higher than the true level. If you check right after driving, you'll get a false reading and may add oil you don't actually need.
Pop the hood and locate the dipstick. It usually has a yellow or orange handle and is marked with a label that says "Oil" or shows an oil can symbol. Pull it straight out and wipe the oil off with a clean rag or paper towel. Reinsert it all the way until it seats, then pull it out again and read the level. The oil should be between the minimum and maximum marks. If it's at or below the minimum mark, add oil.
Check your owner's manual to find out what type of oil your car needs. The manual will list a grade like 5W-30 or 10W-40. Use exactly that grade—don't mix types, and don't use a heavier or lighter oil than specified. Using the wrong oil can reduce fuel economy, increase engine wear, or cause the engine to run too hot or too cold.
Add oil slowly and check again after a minute. It takes time for added oil to drain down to the pan where the dipstick reads it. Add a little, wait, check, and repeat until the level is between the minimum and maximum marks. Overfilling is just as bad as underfilling—too much oil can damage seals and cause leaks.
When to check more often than monthly
If your car is burning oil—meaning the level drops noticeably between oil changes—check every two weeks or before any drive over 100 miles. A car that burns a quart every 1,000 miles is not unusual, especially if it has over 100,000 miles on it. A car that burns a quart every 500 miles or less should be inspected by a mechanic to rule out a leak or worn piston rings.
New cars under warranty should not burn oil at all. If yours does, take it to the dealer and have them document it. Some manufacturers will replace the engine if it burns oil within the first few years.
Older cars, turbocharged engines, and high-performance engines all tend to use more oil. If you own one of these, monthly checks may not be enough. Check every two weeks or every 500 miles, whichever comes first.
What to do if the oil level keeps dropping
If you're adding oil every month and the level keeps falling, you have either a leak or internal wear. A leak is easier to fix: you'll see oil spots under the car where you park, or you'll smell burning oil while driving. Park over a clean surface overnight and check for drips in the morning. If you find oil, have a mechanic locate and repair the leak.
If there's no visible leak but the oil keeps dropping, the engine is burning it internally. This happens when piston rings wear out, valve seals fail, or the engine is straightforward old. A mechanic can run a compression test to confirm. Depending on the car's age and value, you may choose to keep adding oil until the engine fails, or to have the engine rebuilt or replaced.
Don't ignore a dropping oil level hoping it will stabilize. It won't. The sooner you find out whether it's a leak or wear, the sooner you can decide whether to repair it or plan for replacement.
Oil changes and dipstick checks work together
Checking the oil level between changes is not a substitute for regular oil changes. Oil degrades over time and loses its ability to protect the engine. Your owner's manual specifies how often to change the oil—usually every 5,000 to 10,000 miles for modern cars, or every 3,000 miles for older ones. Follow that schedule even if the level never drops.
When you get an oil change, the technician should check the level and top it off if needed. But don't rely on that alone. Checking monthly keeps you aware of how your car behaves and catches problems between services.
Frequently Asked Questions
Can I check the oil while the engine is still warm?
You can, but the reading will be inaccurate. Hot oil expands and sits higher on the dipstick than it actually does when cool. Wait at least five minutes after turning off the engine, or check in the morning before you drive. If you must check while warm, add less oil than the dipstick suggests and recheck after the engine cools.
What if I can't find the dipstick?
Some newer cars don't have a traditional dipstick. Instead, they have an electronic oil monitor that displays the level on the dashboard. Check your owner's manual to see if your car has one. If it does, the manual will explain how to read it. If you can't find either a dipstick or an electronic display, contact your car's manufacturer or a dealer.
Is it bad to add oil if the level is already at the maximum mark?
Yes. Overfilled oil can damage the engine seals, cause leaks, and reduce fuel economy. It can also cause the engine to run hotter than it should. If you accidentally overfill, have a mechanic drain the excess, or you can carefully siphon some out yourself if you're comfortable doing so.
How do I know if my car is burning oil or leaking?
A leak leaves visible oil spots under the car where you park. Burning oil produces a smell like burnt toast or rubber while you drive, and you may see blue smoke from the exhaust. If you see spots, have the leak fixed. If you smell burning oil but see no spots, the engine is burning it internally and needs a mechanic's inspection.
Do I need to check the oil if my car has a low-oil warning light?
The warning light is a safety net, not a substitute for regular checks. It only comes on when the oil level is already dangerously low. By then, you may have already driven on low oil and caused damage. Check monthly so you catch a dropping level before the light appears.