Lawn Mower Oil: How to Pick the Right Type

When you take the lawn mower out of the garage after its winter break, does it seem like it’s not running as smoothly as last year? If you can’t remember when you last changed the oil, it’s probably overdue. But what type of oil does your lawn mower take? That depends on the lawn mower engine, the size of the mower, and the mower type. There is no one-size-fits-all answer. 

When Does my Lawnmower Need an Oil Change?

New mowers may need an oil change after the first 10 hours of use. Check your operator’s manual to make sure. Generally, lawn mowers need an oil change every 25 to 50 hours of lawn care. Always check the oil level with the dipstick in the middle of summer, to see where the oil level is and whether your lawn mower could use a top-off.

Types of Lawn Mower Oil

There are two types of oil for lawn mowers: motor oil and small engine oil. Briggs & Stratton, the largest producer of engines for outdoor equipment, found 48 percent of people surveyed believe automotive oil and small engine oil are the same. They are not. There are some major differences between the two, and you shouldn’t use them interchangeably. “Air-cooled engines run hotter than automotive engines,” says Kevin Wenger Sr., owner of Wenger Equipment in Athens, Wisc. He adds, “The oil temperature in a small engine can reach 280-300 degrees Fahrenheit … nearly 100 degrees hotter than the oil in a typical car.” Small engine oil is designed for high-temperature environments and protects the engine from overheating.

Motor Oil

Motor oil is designed for larger motors typical of automobiles, riding mowers, and deluxe push mowers. You can buy this type of oil at gas stations, hardware stores, and auto parts stores. While some mower owners believe regular engine oil is acceptable for lawn mowers, they could be damaging the engine.

Motor oil meant for automobiles and tractors has a high viscosity. The thick fluid may clog up your push mower, causing irreversible damage. A good mower is an investment, and the last thing you want to do is ruin it doing some routine maintenance.

Motor oil meant for automobiles and tractors has a high viscosity. The thick fluid may clog up your push mower, causing irreversible damage. A good mower is an investment, and the last thing you want to do is ruin it doing some routine maintenance.

Small Engine Oil

Two-stroke engines– common in outdoor power equipment such as chainsaws, weed trimmers, snowblowers, and push mowers– need small engine oil. The reason is simple: a two-cycle engine doesn’t have separate compartments for oil and gasoline. The result is a louder, smokier machine that doesn’t stall under various types of engine load. It also means that owners have to mix the fuel and oil before adding it to the tank.

The gas and oil are mixed at a ratio of 32:1 or 50:1, depending on the machine. Check your owner’s manual to make sure you have the right ratio. Small engine oil, also known as two-stroke oil, is lightweight to ensure even-mixing and smooth engine operation. You’ll find it at any auto parts store or in the garden section of a hardware store.

All engine oil is rated by viscosity. You’ll find that number on the label. Find the number and follow these steps for finding the right oil type.

6 Ways to Pick the Right Lawn Mower Oil

  1. Check your operator’s manual to see if the manufacturer recommends motor oil or small engine oil; look for the viscosity recommendation.
  2. Choose an SAE 30 oil if you live in an area with warmer temperatures (over 40º F).
  3. Choose an SAE 10W-30 oil if you live in an area with a wide temperature range (0-100º F).
  4. Choose a synthetic oil (SAE 5W-30) for much colder temperatures (below 40º), and very high temperatures (up to 120º).
  5. Choose a heavy-duty synthetic oil, such as Vanguard 15W-50, for continuous use, such as commercial lawn mowing or mowing many acres at a time.
  6. Look for a high-quality detergent oil classified “For Service SF, SG, SH, SJ” or higher.

The Bottom Line

Choosing the right oil for your lawn mower will help you to avoid engine problems and can contribute to many years of hassle-free mowing. When you treat your mower well, it will respond by treating your lawn well. A smooth-running mower lets you get the job done and spend more time enjoying your lawn than taking care of it.

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Written by Jackie Greene

Jackie Greene is a blogger, gardener, and nutrition enthusiast. She enjoys creating organic meals for family and friends using the fresh ingredients she produces from her backyard homestead.

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!

About Wikilawn

Wikilawn’s mission is to provide the best resources and information to help you enjoy your outdoor spaces the way you want. Whether you are a DIY, lawn-loving, gardening guru, or someone who wants help in picking a local lawn care professional, we can smooth your path to a beautiful backyard!