What a dipstick tells you and when to check it

A dipstick is a thin metal rod that measures how much oil is in your engine. It lives in a tube that goes down into the oil pan, and you pull it out to see the level marked on it. The mark tells you whether your engine has enough oil to run safely, or whether you need to add more before driving.

Check your dipstick when the engine is cold — ideally before you start driving in the morning, or at least five minutes after you turn the engine off. A warm engine gives a false reading because the oil expands as it heats up. If you check it while the engine is running or when ready after shutting it down, the reading will be higher than it actually is.

Most cars need an oil check once a month, or before a long trip. Older cars or those with higher mileage may need checking more often. Your owner's manual will tell you the interval for your specific vehicle.

Key Takeaways

  • Always check the dipstick when the engine is cold, at least five minutes after the engine has been off.
  • The dipstick has two marks — minimum and maximum — and your oil level should fall between them.
  • If the level is at or below the minimum mark, you need to add oil before driving the car.
  • Wipe the dipstick clean on a rag or paper towel before reinserting it, so you get an accurate reading the second time.

Locating the dipstick under your hood

Open your hood and look for a handle sticking up from the engine block. The handle is usually bright yellow, orange, or red — manufacturers make it visible so you can spot it easily. On some cars it has a label that says "Oil" printed on it.

If you cannot find it by looking, check your owner's manual — it will have a diagram showing exactly where the dipstick is located on your engine. The location varies by make and model. On some vehicles it is near the front of the engine; on others it is toward the back or to one side.

Once you have located it once, you will recognize it when ready the next time. Take a photo with your phone if it helps you remember the spot.

Pulling out the dipstick and reading the level

Grasp the handle firmly and pull straight up. The dipstick will slide out of its tube. You may feel slight resistance — that is normal. Do not twist or wiggle it side to side; just pull steadily upward.

Look at the end of the dipstick. You will see two marks or lines etched into the metal. One is labeled "Min" or "Low" and the other is labeled "Max" or "Full." Between these two marks is a crosshatched or textured area. The oil on the dipstick will have left a wet mark showing where the level sits.

Your oil level should be somewhere between the minimum and maximum marks. If the wet mark is at the maximum line, your oil is full. If it is between the two marks, your oil level is acceptable. If the wet mark is at or below the minimum line, you need to add oil.

What to do if the reading is unclear

Sometimes the oil does not leave a clear wet mark on the dipstick, especially if the oil is very dark or if the dipstick is dirty. In this case, wipe the entire dipstick clean using a rag, paper towel, or old cloth. Wipe from the handle end down to the tip, removing all oil residue.

Reinsert the clean dipstick all the way into its tube until it seats at the bottom. You will feel it stop when it is fully inserted. Wait two or three seconds, then pull it straight out again. This time the oil should leave a clear, visible mark that you can read accurately.

If the mark is still unclear after a second wipe and check, the oil may be very low or the dipstick itself may be damaged. In either case, add oil and check again in a few days. If the problem persists, have a mechanic inspect the dipstick.

Adding oil if the level is low

If your reading shows the level is at or below the minimum mark, you need to add oil before driving. Locate the oil filler cap on top of the engine — it is usually a large plastic cap with an oil can symbol printed on it. Twist it counterclockwise to remove it.

Pour the correct type of oil into the opening slowly. Your owner's manual tells you which grade and type your engine needs — common grades are 5W-30 or 10W-40, but yours may differ. Do not overfill. Add a small amount, wait a minute for it to drain down into the pan, then check the dipstick again using the wipe-and-reinsert method.

Repeat this process until the level reaches the maximum mark. Once you are done, twist the oil filler cap back on clockwise until it is snug. Do not overtighten it.

Understanding what the marks mean

The minimum mark is the lowest safe level for driving. If your oil is below this line, you risk engine damage from inadequate lubrication. The maximum mark is the highest level the pan can safely hold. Overfilling past the maximum mark can cause oil to leak from seals or be burned off during operation.

The space between the two marks is your normal operating range. Most drivers do not need to worry if the level drifts slightly between checks. However, if you notice the level dropping significantly between monthly checks — more than a quart in a month — your car may have an oil leak or may be burning oil abnormally. Have a mechanic inspect it.

Some newer cars have electronic oil level sensors instead of a physical dipstick. If your car has this system, the oil level will display on your dashboard or in your vehicle's information screen. Check your owner's manual to see which system your car uses.

Frequently Asked Questions

Can I check the oil while the engine is warm?

You can, but the reading will be inaccurate. Warm oil expands and sits higher on the dipstick than it actually does when cold. Wait at least five minutes after the engine cools, or check it the next morning before starting the car. A false high reading might cause you to skip an oil change you actually need.

What if the dipstick shows oil but the warning light is on?

The oil pressure warning light indicates a problem with oil circulation, not necessarily the oil level. Even if the dipstick shows adequate oil, the light means the engine is not pumping oil properly. Stop driving and have a mechanic check the oil pump and pressure sensor. Do not ignore this light.

How much oil should I add if the level is low?

Add a small amount — about half a quart — then wait a minute and check again. Repeat until the level reaches the maximum mark. Adding too much at once can cause overfilling. Your owner's manual lists the total oil capacity, which helps you understand how much the space between the marks represents.

Is it normal for oil level to drop between checks?

Slight drops are normal as the engine burns a small amount of oil during operation. If the level drops more than a quart between monthly checks, or if you see oil spots under your car, you may have a leak or excessive oil consumption. Have a mechanic inspect the engine.