Here's What You Should Know About Topping Off Your Engine Oil

Did you know that opening the hood and explaining how to check the oil is a part of the driver's license exam in both the U.K. and Ireland? It should probably be that way everywhere. Knowing how to check and top off your oil used to be one of those things drivers were expected to know, like changing a flat tire or jump-starting a car. But if you don't know where your car's dipstick is, don't worry. We're here to help.

It's a good idea to check your oil once every few weeks. It's pretty simple — you'll just need a funnel and a rag or paper towel. Park your car at a level spot. Usually, where you've stopped to fill your gas tank is pretty level and convenient for this. Locate the oil dipstick, which is typically near the front or side of the engine. Pull it out, wipe off the tip, then re-insert it. Pull it out again and look at the markings near the tip to determine if your car's oil is low.

If it is low, unscrew the oil filler cap and insert the funnel. Pour in just enough oil to fill it, but be careful not to overfill. You don't need to worry about getting the oil all the way to the "MAX" line on your dipstick. It's actually better to fall a little short of that, while getting it in the hash marks, than to overfill. Wait a few minutes, wipe the dipstick off, and check the oil again. Wait a few more minutes after topping off your oil to drive the car. If you have to add oil every time you check it, consider these three big reasons your oil level drops fast.

Checking your oil is pretty simple, and it's best to do it when the engine is cool. The first step is locating your car's dipstick, if it has one — many new cars monitor oil levels electronically instead. The oil dipstick is a long, flexible metal wand that goes into your car's oil sump through a thin shaft. When you pull the dipstick out, you'll see marks that indicate how much oil is in your car. To find the dipstick, locate its little handle (big enough for a finger to fit through). The handle is usually a round yellow or orange ring or a flat yellow or orange handle. Once you locate the handle, pull the dipstick all the way out, wipe off the tip of the dipstick with a paper towel or rag, then re-insert it, pushing it all the way in. Take it back out. Don't wipe it off this time.

Now, how do you read a dipstick? Typically, you're looking for a cross-hatched area near the tip. Something along the lines of "LOW" or "MIN" (for minimum) might be printed along the bottom of the cross-hatched area (between the cross-hatching and the tip). You might see "FULL" or "MAX" just above the cross-hatched area. If you find it hard to see where the oil is on the dipstick, a handy trick is to look at the dipstick from the side or the flip side.

How often should you check your oil? Some drivers check it once every two weeks, or once every 1,000 miles. Some just do it every other time they fill their gas tank. If you have a newer car that doesn't have a dipstick, just go by the readings on your dash or screen.

To add oil, you'll need to locate the oil filler cap. It is usually located right on top of the engine, and marked with a picture of an oil can. Unscrew the cap and place a funnel in the hole. If the oil is below the "LOW" or "MIN" line on the dipstick, add a quart of oil. If it's between the "MIN" and "MAX" lines, you don't have to add oil. 

But you still want to top off the oil anyway. Start with a small fraction of a quart so you don't overfill. Make sure you're pouring the oil correctly. Wipe off the dipstick and re-insert it. Wait a few minutes for the oil to make it all the way down into the sump, then pull the dipstick out again to check the oil level. Wait five to 10 minutes after you top off the oil for it to flow through the engine before driving the car.

Motor oil comes in various weights or viscosity ratings, like "10W-40" and "5W-30". How can you tell which kind of oil to put in your car? The owner's manual is always a good source. If you don't have it, Google is your friend. Not ChatGPT, though – AI tends to "hallucinate." If you do ask one of those AI chat programs, ask it to link to a source. The nice people at auto part stores, like AutoZone and Advanced Auto Parts, can look it up for you as well, and they don't hallucinate.

Checking and topping off your car's oil is one of the easiest things you can do to maintain your car. Do it once, and you'll never forget how.