We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Should I Consider When Buying Motor Oil?

Mary McMahon
Updated May 23, 2024
Our promise to you
WikiMotors is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WikiMotors, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Motor oil is a crucial component in engine care. The oil lubricates the moving parts of the engine, prolonging the life of the engine and making the car run more smoothly. However, as oil is used, it will start to degrade and collect grime. Therefore, it needs to be changed frequently: most automobile mechanics recommend that oil be changed every 3,000 miles (4,828 kilometers). When the oil is changed, the oil pan is completely drained and the oil filter is replaced before fresh motor oil is poured in.

Between oil changes, the motor oil may need to be refreshed occasionally. It is important to buy the same kind of motor oil that the mechanic used when the oil was changed: for example, if the mechanic put in 10W-40 oil, you should also use 10W-40 oil when you top off your oil. Therefore, you should think about what kind of motor oil you need when you are changing your motor oil, not picking up a quart to top off with. There are a number of things that you should consider when changing your motor oil, to ensure that your car will perform at a high standard for you for years to come.

The first thing to think about when buying motor oil is what type of oil you want to use. There are two bases of oil available: one uses petroleum, and the other is a synthetic. Petroleum based motor oil is cheaper, but also gives out faster and leaves more particulates in the engine. Synthetics are designed for high performance, and generally believed to be superior. They are also more expensive: if you do not engage in heavy driving, especially prolonged freeway driving, synthetics may not be necessary. Most mechanics also agree that motorists should avoid petroleum oils with additives in them, because the additives do not impact performance enough for the potential engine clogs to be worth it.

The second issue is the viscosity of the motor oil. Thin motor oil will tend to burn and break down at the high temperatures of an actively running engine. Therefore, a higher viscosity is needed so that the oil can stand up to high temperature use. However, high viscosity oil is too sluggish when a car is being started, and will not flow through the engine. Therefore, motor oil is manufactured in combined viscosities which behave differently at different temperatures. The viscosity level of oil is tested and determined by the Society of Automotive Engineers (SAE), and the SAE ratings are listed on bottles of motor oil in multiples of 10, and more rarely, five.

In hot weather, you will need oil motor oil of a higher viscosity, because the heat will interplay with the engine to have an impact on the oil. People living in hot areas or changing their oil before the summer should think about oils in the 10W-50 range: the “W” means that the oil is suitable for winter use as well. In cold weather, low viscosity oil is needed, because the cold will make the oil sluggish—10W-30 or 40 is more appropriate. For people in temperate climates, 10W-40 oil is ideal.

Several others things on the label of a bottle of motor oil will provide information about its quality: the flash point, percentage of sulfated ash, and percentage of zinc. The flash point refers to the point at which vapors rising from the oil will ignite: the higher the flash point, the better the oil quality. The percentage of sulfated ash refers to the detritus left behind as the oil is used: the lower this number, the better the oil. Finally, zinc protects the parts of your engine where there is metal to metal contact, but too much zinc can clog the engine: for most automobiles, the zinc percentage should hover around 0.1%.

WikiMotors is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Mary McMahon
By Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WikiMotors researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Discussion Comments
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a...

Learn more
WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.

WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.