What Lawn Mower Oil Type Should You Use? A Complete Guide

The right kind of lawn mower oil is the lifeblood of your mower’s engine. Imagine it as the smooth, protective barrier keeping every piston and gear moving flawlessly, even under the fiercest sun or hardest turf. Knowing which oil your mower needs can determine whether it starts quickly or breaks down early, whether it hums along with a 2-stroke or a 4-stroke motor.

Why Lawn Mower Oil Matters

As an internal combustion engine, a lawn mower requires good-quality oil for proper functioning. Even the smallest gas engines have moving components working at high speeds and under a lot of heat. This is why the correct lawn mower oil is essential tolubricate and cool.

Without oil, your mower’s motor can overheat, seize up, and potentially suffer damage that is difficult to repair.

Lawn Mower Oil Types

Motor oil comes in different grades with varying viscosity and behaviors at different temperatures. Most mowers have what are called four-stroke engines. This means they burn straight gasoline as it comes from the service station pump, but they also require motor oil to be added separately to the crankcase of the engine. For many models, 10W30 is a common and reliable oil grade. While your owner’s manual is always the best source for specifics, in most cases, 10W30 is a safe bet when choosing oil for 4-stroke engines.

Any brand of oil that’s suitable for cars or trucks will work fine in your mower. All reputable oil includes a service rating in addition to a viscosity rating. Look for oil that’s designated SF, SG, SH, SJ or higher.

• Single Grade Oil: A single grade level oil typically without additives to change its viscosity and represents only at higher temperatures (100°C).
• Multi-Grade Oil: A multi-grade level oil that uses additives to provide better viscosity at a range of temperatures.
• Synthetic Blend Oil: A mixture of regular and synthetic oil with additives to help perform at colder temperatures without the cost of a full synthetic oil.
• Full Synthetic Oil: An artificially created lubricant with a wide range of benefits designed for use in high-performance and commercial engines

Some lawn mowers have two-stroke engines, and these require oil in a different way than four-stroke engines. All two-stroke engines burn gasoline and oil at the same time. In the case of lawn mowers, two-stroke engine oil is mixed with the gasoline before it goes into the tank. Mixing ratios of gas to oil vary, but usually range from 30:1 (4-1/4-oz. of oil to one gal. of gas) to 50:1 (2-1/2-oz. of oil to one gal. of gas). The owner’s manual for your lawn mower lists the mixing ratio of gas to oil.

While two-stroke models are becoming less common due to emissions regulations, they’re still in use. Not sure which engine type your mower has? The owner’s manual is the most reliable place to find that information.

How to Choose the Right Lawn Mower Oil

Choosing the right lawn mower oil type depends on your engine and climate. Some professionals feel that more expensive “small engine oil” is the only safe choice for mowers with four-stroke engines. But that’s not quite right. For small engines, high-quality standard motor oil used for automobiles and trucks is usually the best oil, providing great performance for the majority of four-stroke lawn mowers.

Have a two-stroke engine instead? Any two-stroke motor oil made for air-cooled engines—like those in chainsaws, water pumps or string trimmers—will operate just as well in your mower. When choosing oil for 4-stroke engines or deciding the proper gas-to-oil ratio for two-stroke vehicles, always consult your owner’s manual.

• SAE 30 Oil: Engine oil best suited for warmer temperatures.
• SAE 5w-30 Synthetic Oil: Synthetic mower oil is good for warm and cold weather use.
• SAE 10w-30 Synthetic Oil: Synthetic oil that can help in colder temperatures.
• SAE 15w-50 Synthetic Oil: Synthetic oil is typically used for high-end and commercial engines.

The best way to mix gas and oil for a two-stroke engine is to put the required amount of oil into your empty gas can, then go to the gas station and fill it up. Before using the mixed gas, give the can a shake to so the oil and gas are properly mixed.

What is Synthetic Oil, and Should I Use It In My Lawn Mower?

Should I use synthetic oil in my mower? Absolutely, especially if you’re looking to maximize performance and longevity. Unlike traditional lubricants made from crude oil, synthetic oil is designed from chemical components to provide better engine protection, smoother operation and improved resistance to severe temperatures.

Changing synthetic oil

Briggs & Stratton, one of the top small engine makers, claims synthetic oil does not alter the advised oil change intervals. Synthetic oil might provide more steady performance between changes, but you’ll still have to keep frequent service.

How Often to Check and Change Lawn Mower Oil

Only lawn mowers with four-stroke engines have oil that can be checked and changed. Tuning up a lawn mower at least once a season, which includes changing the oil, is essential for maximizing fuel economy and extending the life of the engine.

These are among the most important lawn mower oil change tips to follow for long-term performance.

If your four-stroke engine lawn mower is new, change the oil after the first three to five hours of use. As parts of a new engine wear initially, the internal movement of parts releases tiny metal filings into the oil that will cause excess wear if left there.

• Walk-Behind Mowers: Change oil in the mower at least once a season or every 50 hours of use.
• Riding Mowers: Change oil in the mower at least once a season or every 100 hours of use.

The owner’s manual for your lawn mower lists the amount of oil required, but you’ll do fine following the dipstick or oil level mark on every four-stroke lawn mower engine. This is key when choosing oil for 4-stroke engines and ensuring proper maintenance.

How to Check Lawn Mower Oil

Before each mowing session, you should check your lawn mower’s oil level and top it off if necessary. To do so:

• Place your lawn mower on a level surface and let it sit idle for a few minutes so that the engine oil can settle.
• Remove the oil cap and wipe the dipstick off with a clean cloth. Put it back into the oil tank and tighten the cap.
• Once again, remove the cap and check the oil level on the dipstick. The level should fall between the “full” and “add” marks. There may be differences in the appearance of these marks depending on the brand of mower you own. Some dipsticks may have only two holes to indicate “full” and “add”, or a cross-hatched pattern. Either way, you want the oil level to be between the two holes or marks. As close to the “full” side as possible without exceeding it.
• Whenever more oil is needed, add it in small increments and repeat this process between each addition to prevent overfilling the engine.

Signs Your Lawn Mower Needs an Oil Change

Knowing when to change your lawn mower oil is just as important as how to change it. Although your mower might indicate that it needs new oil sooner, following the manufacturer’s advised timetable is absolutely vital. Here are some signs to look out for:

• Dark or dirty oil: Clean oil is typically golden or amber in color. If the oil seems dark, thick, or gritty when you inspect it, it is time for a change.
• Increased engine noise: Oil that’s lost its lubricating properties can cause the engine to sound louder or rougher than usual.
• Overheating: Old or low-quality oil cannot cool the engine correctly, which can cause your mower to feel abnormally hot during or after usage.
• Poor performance or stalling: Dirty oil may be interfering with engine function if your lawnmower begins to struggle, stalls frequently, or loses power.
• Excessive exhaust smoke: Although some smoke is normal, extreme exhaust smoke can be a sign of low or old oil.

Monitoring these indicators and adhering to fundamental lawn mower oil change advice helps to save engine life and keep best performance. Especially if you use your mower often, consult your owner’s manual and follow a consistent schedule if you are unsure.

How to Change Lawn Mower Oil

When changing the oil in a lawn mower, follow these steps to complete this simple maintenance task.

FAQs

How much oil does a mower take?

Depending on the make and model, push lawn mowers typically hold between 13.5 and 22 ounces of oil, while riding mowers have a capacity between 48 and 64 ounces. Always refer to your mower’s operator’s manual for the recommended oil amount specific to your engine.

What does SAE stand for in oil?

SAE is the acronym for the Society of Automotive Engineers, the organization that sets standards for automotive oil worldwide.

Can I use car oil in a lawn mower?

Yes. As previously noted, engine oil made for cars and trucks is the highest-quality oil on the market, and it works optimally with nearly all four-stroke engines.

What happens if I put the wrong oil in my lawn mower?

Depending on the mismatch, using the wrong type of oil in your mower can cause several problems. Too thick (high-viscosity) oil could not circulate properly, particularly in cold weather, therefore producing inadequate lubrication and more engine wear. If it’s too thin, it might not sufficiently protect at greater operating temperatures, possibly causing overheating or engine failure. Oil types that are incompatible could potentially leave hazardous deposits or degrade more quickly.