Your engine’s lifeblood—what type of oil should you use?

Written by Gene Caballero on February 03, 2017

The heart is one of the most important organs in an individual’s body. It acts like a dual-chambered pump that circulates blood and provides the body with oxygen and nutrients it needs to survive. Needless to say, blood is just as important as the heart; it brings a steady supply of essential food and oxygen to the body’s cells. Even the heart couldn’t survive without blood flowing through the vessels that bring nourishment to its muscular walls. Without blood, humans would be unable to fight infections, get rid of the body’s waste products, keep warm, or cool off.

When looking at a lawn mower engine, one can think of it as the heart. It provides the power to rotate the blades and turn the wheels. The motor oil one puts in the engine is a lawn mower’s lifeblood, which travels through all parts of the engine, lubricating each component so each can perform its designated task. Just like the blood that circulates through the body, the cleaner the motor oil is, the better the engine will run. With all of the different choices in motor oil, how does one ensure using the proper type? Below are a few tips to keep in mind when changing the blood in your engine.

Practice regular oil transfusion—Oil in a lawn mower needs to be changed regularly to ensure its cleanliness and effectiveness. Most manufacturers will recommend changing the oil every 20-50 hours of operation. Depending on whether one just mows their home or professionally mow lawns in Kissimmee, Florida or cut grass in Roswell, Georgia, it’s best to refer to the owner’s manual to make the best informed decision. Keeping a log of how many hours the mower has been used will help maintain the proper oil changing regiment.

Understand the oil—The Society of Automotive Engineers (SAE) developed a categorization of motor oils in which the viscosity, or thickness, is measured (0W-30, 5W-30, etc). Viscosity is the fluid’s resistance to flow. Thin fluids have a low viscosity, and fluids that are thick have high viscosity. The oil in a lawn mower’s engine changes in viscosity density when it is either heated or cooled.

So what does SAE-0W-30, 5W-30, or 10W-30 even mean? The higher the initial number, the thicker the oil—0 is like water and 10 is like honey. The “W” stands for winter and represents the viscosity of the oil in cold conditions—meaning it has been tested at very low temperatures such as -30° Fahrenheit and can properly lubricate in that environment. The number 30 at the end represents how well the oil flows after it has been heated to 212° Fahrenheit or higher. Hence 0W-30, 5W-30, and 10W-30 all have the same viscosity at 212° Fahrenheit, but at lower temperatures, 0W-30 has the least viscosity and 10W-30 has the highest viscosity.

Know the environment—Oil behaves differently at various temperatures. The outdoor environment should help determine the correct oil for any lawn mower engine. Even though lawn mowing normally occurs during the warmer months, lawn mowers can still be used in the cooler months for leaf mulching and/or removal. Other equipment, such as snow blowers, will solely be used in the winter months and will certainly have different oil requirements. Combine the information below and the information from the owner’s manual to make the best engine oil decision.

Regularly changing the oil in any mower is essential to its prolonged life. Since the oil is such a vital component of the internal operations, it needs to be treated like the mower’s life depends on it—and it actually does. When to change the oil, the different types of oil, and the best oil for the mowing environment are essential to maintaining the heart of your mower.   

Hi, I'm Gene Caballero and I'm the co-founder of GreenPal . At GreenPal, we're helping hundreds of thousands of Americans solve one of the trickiest problems: a reliable, fast, and affordable way to get lawncare taken care of. On behalf of GreenPal, I've been featured in the Indianapolis Star, the Sacramento Bee, Entrepreneur,, and dozens more. Please feel free to say hi on Twitter or connect with me on LinkedIn.

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