How to Check Your Car's Oil Level and Add More When It's Low

March 14, 2018

Knowing when and how how to check your engine oil is an essential part of vehicle maintenance because. Oil is what keeps your engine lubricated. When it runs low or becomes dirty, it has the potential to ruin your engine or at least muck it up, leading to costly (and totally preventable) repairs. 

When to check your oil

The obvious sign it's time to check your oil level is if your low oil level light is on. Even without a warning light, it's a good idea to check your oil once a month or every other time you fill up with gas; whichever comes first. That way, you can be sure you're catching any potential problems before they have a chance to damage to your engine.


When to check oil: Hot vs. cold

Historically, automakers and mechanics have recommended that oil be checked when a vehicle's engine is cold. At the very least, you should wait at least 10 minutes after shutting off your car before checking. There are several reasons for this. First, the oil dipstick is generally calibrated for cold oil. Heat can make the oil expand, which would then give you an inaccurate reading when checking the levels.

Doing it on a cool engine also ensures you don't get burned, and that all the oil is in the pan. With that said, some automakers realized that people weren't following these instructions and were getting false results because they checked while the engine was warm, so they recalibrated their oil dipsticks to be read while warm. Ford Motor Company, which also includes Lincoln and Mercury, is one example of a big-name brand that made the switch with newer models.

Bottom line: Automakers do not have a standardized method for when or how to check oil, but there do tend to be commonalities across most vehicles. If this quick guide doesn’t seem to match your particular vehicle or you’re unsure how to proceed, always refer to your vehicle’s owner’s manual.

How to check your oil

Before you begin, always make sure your vehicle is parked on a flat surface and that the parking brake is on. Then, pop the hood.

1) Locate the oil dipstick

find the dipstick

The oil dipstick is usually near the front of the engine toward the passenger side. You'll note that it typically has a red, yellow or orange pull tab on top. The tab may be circular or squared-off, and is generally marked with an oil can symbol. The stick will be set inside a thin guide about the width of a pencil or may be integrated into the oil cap. Be aware that, if you have an automatic transmission, you'll also see a transmission fluid dipstick near the rear of the engine. This should be marked as well, and you'll want to take care not to confuse the two.

2) Remove the oil dipstick and examine the color and consistency

removing the dipstick

When fresh oil goes in, it's usually a golden or honey color, but it gets dirty quickly. You should expect it to be a shade of brown or black and free of debris. You'll want to change your oil or take your vehicle to a mechanic if you note:

  • Dark black or nontransparent oil
  • Sludgy oil
  • Grains or chunks (metal and dirt deposits)
  • A putrid smell
  • Milky appearance, looks kind of like coffee with milk in it (could signal a coolant leak)

3) Wipe the oil dipstick and measure your level

wiping dipstick

If the color and consistency look OK, you'll then want to make sure your vehicle has enough oil. Use a lint-free rag or towel to remove all oil on the stick, then slide it back into the guide it came from.

Pull it out again, and look to see where the line of oil stops. Oil dipsticks can be marked in several ways, but they all have some kind of high-low marking to show you an acceptable range. In the image below, the leftmost hole or marking is the high side. The rightmost hole or marking is the low marking. You want your oil to fall in the middle.

checking oil level

Too high: If the level is high (and it's not because you've added excess oil), it often signals a problem such as a coolant leak or water in the oil tank. These should be addressed by a mechanic right away.

Too low: If the level falls below the lowest marking, it’s time to add more oil (see below).

How much oil does my car need?

Motor oil is definitely not one-size-fits-all. Figuring out how much oil your car holds will require you to read your owner's manual. If your check indicates you have low oil, you’ll want to add half a quart at a time.

Be extra careful with hybrids vehicles, as they have a high sensitivity to oil levels and you could cause warning lights to turn on.

What type of oil does my car take?

Both Mobil and Pennzoil have easy-to-use automated product selectors that make recommendations based on your vehicle type and age. You can use these tools, check your manual, or talk to a professional to be sure. When comparing oils, you’ll want to look for:

Viscosity: Oil needs to be able to flow freely through an engine in order to be effective, yet thicker oil seals and lubricates better. A thick oil might be good in the summer, but it could be problematic in the winter. For this reason, oils come with different additives and are rated with viscosities, so you can be sure you're getting the right coverage. You'll see this resistance to flow represented as a series of numbers and letters on the oil. The first number in the series represents the resistance to flow at 0° F, while the numbers after the letter are at 212° F. One common example is "0W-20". Your owner's manual will tell you which viscosity is best for your vehicle.

Premium conventional: Most vehicles use conventional oil, though the recommended rating will differ.

Full synthetic: Synthetics are designed for high-tech engines, like those used in most sports cars, and perform better under cooler conditions.

Synthetic blend: Oftentimes, SUVs and the like require synthetic blends because they’re designed for heavier loads and higher temperatures.

High-mileage: As engines age and parts wear out, traditional varieties don't perform as well. Vehicles with more than 75,000 miles often do best with a high-mileage option.

How do I add oil to the car?

Adding oil to a car is simple. The oil cap is usually easy to identify; it's usually on top of the engine, near the oil dipstick. Sometimes the dipstick is part of the cap.

To do the oil top-off, simply remove the cap and slowly pour in the oil. You may find it helpful to use a funnel, but if you pour slowly and carefully, you may be able to get by without one.

Start by adding half a quart. Give it a moment to settle and then measure the level using the oil dipstick. Add more as needed. If you're going through more than one quart every 1,000 miles, it's a good idea to have your mechanic take a look.

About the Author

Kimberlea Buczeke is an automotive expert at RepairPal, the leading online source of auto repair resources and estimates. With many ASE Master certified mechanics on staff who have decades of experience, RepairPal knows all the fine points of car repair.

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