Check your oil level every month and before long trips
You should check your oil level once a month using your dipstick, and again before any drive longer than a few hours. Most cars burn or leak small amounts of oil between scheduled oil changes, so the level drops gradually. Adding oil when the level falls below the minimum mark on the dipstick keeps your engine protected and prevents damage that costs thousands to repair.
The dipstick is usually a yellow or orange handle under the hood. Pull it out completely, wipe it clean with a paper towel or cloth, reinsert it all the way, then pull it out again to read the true level. The oil should sit between the minimum and maximum marks. If it is at or below the minimum mark, you need to add oil.
How often you add oil depends on your car's age, engine condition, and driving habits. Newer cars under 60,000 miles typically need oil added once or twice a year. Older cars, especially those over 100,000 miles, may need oil added every few months. Cars driven mostly in stop-and-go city traffic burn oil faster than those driven on highways.
Key Takeaways
- Check your oil level monthly by pulling the dipstick, wiping it clean, reinserting it fully, and reading where the oil sits relative to the minimum and maximum marks.
- Add oil when ready if the level is at or below the minimum mark, because driving on low oil can damage your engine within hours.
- Use only the oil type specified in your owner's manual — mixing weights or synthetic with conventional can affect engine performance and protection.
- If you are adding oil more than once between scheduled oil changes, have a mechanic inspect for leaks or internal burning.
What oil type to use when adding
Your owner's manual specifies the exact oil weight and type your engine needs. Common weights are 5W-30, 5W-40, 10W-30, and 10W-40. The first number (5W or 10W) describes how the oil flows in cold weather; the second number describes flow at operating temperature. Using the wrong weight can reduce fuel economy, increase engine wear, or cause starting problems in cold weather.
Check whether your car requires conventional, synthetic blend, or full synthetic oil. Conventional oil is the least expensive and works fine for most cars. Synthetic blend offers better protection and lasts longer than conventional. Full synthetic lasts the longest but costs more. You can switch from conventional to synthetic blend or full synthetic at any time, but do not mix them in the same engine.
Buy oil at any auto parts store, gas station, or big-box retailer. A quart usually costs between $3 and $8 depending on the type and brand. Keep a quart or two in your trunk so you can add oil when ready if the level drops unexpectedly during a trip.
How to add oil safely
Park on level ground and wait at least five minutes after driving so the engine cools slightly. Open the hood and locate the oil filler cap — it is usually on top of the engine and labeled with an oil can symbol. Twist the cap counterclockwise to remove it.
Pour oil slowly into the opening, adding about half a quart at a time. Wait a minute for the oil to settle into the pan, then check the dipstick again. Repeat until the level reaches the maximum mark. Do not overfill — oil above the maximum mark can damage seals and cause leaks.
Screw the oil filler cap back on firmly. Wipe up any spilled oil with a paper towel. Start the engine and let it run for 30 seconds, then turn it off and wait two minutes before checking the dipstick again to confirm the level is correct.
Signs you are burning oil too quickly
If you are adding more than a quart of oil between scheduled oil changes, something is wrong. Burning oil at that rate means either your engine has internal wear, your piston rings are failing, or you have a leak you cannot see. Any of these problems will get worse and more expensive if ignored.
Blue or gray smoke from the tailpipe is a sign of internal burning. A dark spot under where you park is a sign of a leak. A burning smell from the engine bay can indicate oil leaking onto hot engine parts. Have a mechanic inspect the engine if you notice any of these signs or if oil consumption suddenly increases.
Some cars are known to burn oil more than others — certain BMW, Audi, and Subaru models burn oil at higher rates than average even when they are working normally. If your car is one of these models, check your owner's manual for the expected oil consumption rate. If you are within that range, you do not need to worry.
Difference between topping off and an oil change
Topping off means adding oil to bring the level back to the maximum mark. An oil change means draining all the old oil, replacing the oil filter, and filling with fresh oil. They are not the same thing. Topping off keeps your engine protected between oil changes but does not remove the dirt and metal particles that accumulate in old oil.
Oil degrades over time and loses its ability to protect your engine. That is why you need a full oil change at the interval specified in your owner's manual — usually every 5,000 to 10,000 miles for conventional oil, or every 7,500 to 10,000 miles for synthetic blend or full synthetic. Topping off extends the life of your current oil slightly but cannot replace a full change.
What to do if you cannot find the dipstick
Some newer cars do not have a traditional dipstick. Instead, they use an electronic oil level sensor that displays the level on the dashboard or infotainment screen. Check your owner's manual to see if your car has this system. If it does, the display will tell you when the level is low.
If your car has an electronic sensor and the display shows low oil, you still add oil the same way — locate the oil filler cap, pour slowly, and check the sensor reading after a minute. Some cars with electronic sensors do not have a way to check the level manually, so you have to trust the sensor reading.
If you cannot locate either a dipstick or an electronic display, consult your owner's manual or call your car's manufacturer customer service line. They can tell you exactly where the oil level indicator is and how to use it.
Frequently Asked Questions
Can I add oil to a hot engine?
You can, but it is safer to wait five minutes after driving so the engine cools slightly. Hot oil can splash or burn you when you remove the filler cap. Letting the engine cool also gives the oil time to drain back into the pan, so your dipstick reading will be more accurate.
What happens if I overfill the oil?
Overfilled oil can damage seals, cause leaks, and reduce engine performance. If you add too much, remove the excess by loosening the drain plug slightly and letting oil drip into a pan until the level is correct, or use a hand pump to siphon oil out through the dipstick hole. Check the level again after removing oil.
Is it normal for my car to burn oil?
Some oil consumption is normal — most cars burn between 500 and 1,000 miles worth of oil per quart. If you are adding more than a quart every 1,000 miles, have a mechanic check for leaks or internal engine wear. Older cars burn more oil than newer ones.
Can I mix different oil brands?
Yes, you can mix different brands as long as they are the same weight and type. Mixing a 5W-30 Mobil with a 5W-30 Castrol is fine. Do not mix different weights or types — for example, do not mix 5W-30 with 10W-40, or conventional with synthetic.
How long does it take for added oil to circulate through the engine?
Oil circulates through the engine within seconds of starting it. Wait about 30 seconds after starting, then turn the engine off and wait two minutes before checking the dipstick again. This gives the oil time to drain back into the pan so you get an accurate reading.