How to Read an Oil Dipstick
The engine oil keeps your moving parts lubricated, reduces friction, cleans deposits from inside the crankcase, prevents corrosion on metal surfaces, and helps keep everything cool. It can only serve its roles effectively if there’s sufficient clean oil in the engine, though. Your dipstick is the device used to check the condition and level to determine if the oil needs to be changed or topped up.
Understanding how to check oil using the dipstick isn’t difficult, even if you’ve never worked under the hood of a car before. It’s an excellent skill to have, and it can save you time and money by keeping your car running at its best between services. Here’s how to read an oil dipstick and how to top off the oil.
Why you need to check oil
When you rub clean, new engine oil from a container between your fingers, it feels clean and slippery. That’s the basic premise for what it does inside the engine too – a slick liquid that keeps fast-moving metal parts separated with a lubricating film. But if you rub old, dark motor oil between your fingers, it feels gritty, and that’s not healthy for an engine.
Engine oil’s condition needs to be checked to ensure it’s fine to be used for longer, but there are other reasons to check oil too:
- All engines consume oil. There’s no such thing as a perfect seal in the cylinders, and all engines will burn a little oil. Normal amounts of oil consumption are determined by the carmaker, and some tolerate up to one quart per 3,000 miles or as much as a quart per 1,000 miles.
- There could be an oil leak. It’s possible for a leak to develop on your engine. Over time, the oil level can drop, and finding low oil levels can spur you to check for and discover the leak.
- It could be contaminated. If water finds its way into the engine, the oil will change from a translucent golden color to milky brown, and that moisture will promote corrosion in the crankcase.
Ideally, you’d check your oil level and condition every time you fill your vehicle’s fuel tank. However, it’s more realistic to check oil dip sticks and top up the oil as required at least once per month.
How to read dipstick oil levels
Using a dipstick is how to check oil in car engines. The technique to check the oil is the same no matter the type of engine or dipstick you have, but the indicators on the dipstick can and do differ between makes and models.
1. Park on a level surface
To get an accurate reading, your car needs to be parked so it’s level from front to back and side to side. Otherwise, the slanted oil level could give a deceiving measurement, leading you to over- or under-filling it.
2. Check the engine cold
The engine oil level should be checked at least 5 to 15 minutes after you’ve parked your car and shut the engine off. That way, the oil has a chance to drain into the oil pan for an accurate measurement.
3. Pull out and clean the dipstick
With a clean lint-free towel or paper towel in hand, pull the dipstick out of the tube. Guide it out carefully, especially toward the end, or you could fling oil droplets onto yourself or around the engine bay. Wipe the oil off the dipstick with your towel.
4. Fully insert the dipstick
Put the dipstick back into the tube, ensuring that it’s inserted fully. If it isn’t put in all the way, your reading will indicate lower than it actually is, and there’s a risk of overfilling the engine oil.
5. Remove and read the dipstick
Again, carefully remove the dipstick from its tube without touching the end. Support the dipstick halfway or so to stop it from bouncing around, making it hard to read and causing drips. Locate the indicators on the dipstick to determine your reading.
Indicators can vary. Some carmakers have an F and L stamped on the dipstick, representing Full and Low. Others have a crosshatched section, Max and Min stampings, or simply a hole marking the low and high marks, and yours could be different still. In any case, it will be well defined on the bottom few inches.
- If the oil shows at or near the Full mark, your level is fine.
- If it’s at or below the Low mark, you need to add engine oil.
- If the oil level is between the marks, it’s still in a normal range, although you may still want to add a little oil for peace of mind.
- If you can’t see any oil on the dipstick, there’s a concerning issue.
The color of the oil should be somewhere between honey brown and amber with a gas engine. If it’s darker, you’re due for an oil change.
How to top off oil
Now that you know how to check oil, the next step is topping it off. Use the exact oil specification your engine needs – you’ll find that on the oil filler cap in most cases or in the owner’s manual. Remove the oil cap and place a funnel there. Don’t try to fill in the dipstick tube as it’s bound to make a mess!
If your oil is below the Low mark, add a quart of oil and recheck. If it’s in the normal range, add 1/4 of a quart at a time until it’s at the Full mark. Be careful not to overfill the oil.
If your oil level is already overfilled or you accidentally add too much, you should drain some to bring it back into range.
If you need engine oil for a top-up or any other parts and fluids for your vehicle, shop at AutoZone. You’ll find everything you need to keep your car in top shape at a great price. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.
FAQ/People Also Ask
The oil level should be between the maximum and minimum marks on the dipstick, otherwise you’ll need to adjust the level.
The upper line indicates the maximum safe oil level and the lower line is the minimum level.
Every engine has a different capacity, so the difference between low and high aren’t constant. However, newer models are around 1 quart difference between the marks.
If the oil level is above the full or max line on the dipstick, it’s overfilled and should be adjusted.
If the oil level is below the minimum mark on the dipstick, it’s low and should be topped up.
