Ideally, you should get your car’s oil changed as often as the manufacturer suggests, anywhere from every 3,000 to 7,000 miles, depending on the vehicle. But something as routine as an oil change is easy to forget. If you notice any of the following three signs when you operate your vehicle, there’s a good chance that you forgot an oil change.

Your Oil Light Comes On If your oil light comes on, then your car is already experiencing a problem that you need to address. The oil light’s appearance is more than a reminder that you need to get an oil change. This light indicates a potential problem with an existing mechanical issue.

In most cases, you need to replace the oil, a situation that’s especially true with newer vehicles. However, your oil pressure could be low as well. A decrease in oil pressure could be caused by an insufficient amount of oil or an oil pump that isn’t working properly. Either way, head to your mechanic soon.

The Oil Looks Dark and Dirty Do you find yourself wondering whether you remembered to get your car’s oil changed? If you can’t recall the last time you changed your oil, then take a look under the hood.

Once you find the vehicle’s dipstick, remove it, wipe off the oil, and reinsert the dipstick into the stem. Then, pull out the dipstick again to check the oil’s color. Wipe the oil onto a white paper towel if you have a hard time seeing the color clearly on the dipstick.

Clean oil has an amber color. As the oil gets dirtier, the oil takes on a darker appearance. Depending on how long you’ve been operating your vehicle since you last changed the oil, the oil may even look black. If your oil is dark, then you should change the oil immediately. Dirty oil cannot lubricate your engine’s moving parts well, putting your vehicle on a road to mechanical malfunction.

Closely Listen to the Engine Since dirty oil can’t do its job, your engine will soon start to complain, sometimes quite loudly. Low oil pressure can cause your engine to make a loud knocking or rapping sound. The sound your hear coming from your engine is the sound of your engine’s rods knocking together, which you do not want to have happen. Damaged rods are expensive to repair.

You may also hear a fast clicking or clapping noise. This sound occurs when low oil pressure causes the upper valvetrain to malfunction. If you don’t address the problem soon, those sounds may become louder and more annoying. Eventually, your engine will stop working. In this case, get your oil changed today.

When it comes to maintaining and caring for your vehicle, an oil change is essential to ensuring your vehicle’s proper performance. Make sure you get your vehicle’s oil changed on schedule, so you can avoid damage or expensive repairs. If you forgot the last time you serviced your vehicle, look for the above three signs as reminders that your vehicle needs an oil change.