How to Check Oil in Car: When & How Often

A guide on checking your motor oil

How to check your engine oil

While some cars consume hardly any engine oil, others can burn off or drip plenty. That's why it makes sense to check your oil level frequently between oil changes, as running with a low oil level increases stress on the engine and can seriously reduce the working life of the oil and the engine.

Some modern cars have an electronic oil sensor that warns you when your motor oil is approaching the minimum safe level. But whether your car has one or not, it's good practice to check your engine oil level manually on a regular basis, especially if you're planning a road trip. After all, sensors and dash lights can both fail without you knowing about it.

Understanding Oil Change Intervals

Oil changes are essential for maintaining engine health. They remove old, contaminated oil and replace it with fresh oil that can properly lubricate and protect the engine's components. Traditionally, it was recommended to change your oil every 3,000-5,000 miles. However, modern technology and advanced synthetic oils are changing the game. In certain conditions, extended oil change intervals (also known as extended drain intervals) are possible, potentially reaching 15,000, 20,000, or even 25,000 miles with the right synthetic oil.

Want to learn more about extended oil change intervals? Read our article, "Castrol Extended Oil Change Interval Mythbusters," to debunk common myths and discover if extended intervals are right for you.

Factors Affecting Oil Change Intervals

The ideal oil change interval depends on several factors, including your driving habits, vehicle age, and engine type. "Severe driving conditions," such as frequent short trips, stop-and-go traffic, towing, and extreme temperatures, can shorten oil life. Always consult your owner's manual for the manufacturer's recommended oil change interval. You might also consider oil analysis to monitor the condition of your oil and determine the optimal oil change interval for your specific vehicle and driving conditions.

Steps to checking engine oil

To check your engine oil level, first make sure to park your car on level ground, then wait at least 10 minutes to let the oil drain out of the engine and back into the sump.
Raise and secure the hood, then locate the top of the dipstick, which is usually pretty easy to see and to reach. Pull it out and use a rag or paper towel to wipe the end clean. Then replace it, making sure it goes all the way in, before immediately lifting it out and holding it in a horizontal position. Near the end of the dipstick there should be two lines, sometimes with a cross-hatched area in between. Ideally, the oil level should be at or near the highest line, though anywhere above the lower line is still OK.
If the oil level is close to or below the minimum mark, you definitely need to top off your oil right away. If the level is mid way, then topping off your engine oil level is optional. Importantly, even if you only need to add a little oil, you must make sure you add the correct type and grade of oil, which you can identify using our quick and easy Oil Selector tool.
It's also important to know that if you have to drive somewhere to buy motor oil - our Where to Buy tool can help you find a nearby retailer or service center that stocks Castrol motor oil - that you again park on level ground and wait ten minutes for the oil to drain into the sump before you make a top-off. That's because over-filling your engine oil is just as bad for your engine as running low, and can cause serious damage, particularly to vehicles fitted with catalytic convertors.
Once you've parked and waited, check the dipstick as before, and add a little oil at a time, cleaning and checking the dipstick after every addition, and making sure that you don't take the level above the 'maximum' mark on the dipstick.

When should you check your oil?

Naturally, it's essential to change your engine oil at the intervals recommended by the manufacturer. But how often should you check your oil level?

In the days before oil level sensors, many drivers checked their oil at the dipstick at least once a week.

Unless you're running an older car or an American classic, that may not be necessary these days. Having said that, it's worth remembering that your motor oil is no less important than any other engine component.

Even if you're driving a brand new muscle car or highly engineered European model, environmental factors such as fuel quality, extreme temperatures or stop-and-go driving can increase the amount of oil your engine uses.

So here at Castrol, most of our people pop the hood and check their oil level at least every couple of weeks, and always right before a long trip. It only takes a minute to check and top off if necessary, and it might add years of reliable, powerful and economical driving to the life of your engine.