How To Choose The Right Oil For Your Lawn Mower

How To Choose The Right Oil For Your Lawn Mower

A beautiful lawn requires some amount of hard work and a lot of care. One of the important aspects of lawn care is regular mowing during the mowing season. You need to make sure that your lawn mower has the right oil to work well. 

Mowing the lawn at least two times a week not only helps keep it healthy and lush but also makes it resilient enough to survive through winter and drought. The taller the grass plants, the deeper their roots, and the thicker the lawn will be. 

A thick lawn is the best defense against insect and fungal infestation, weeds, and other diseases.

Mowing season begins in spring and lasts until late summer or the beginning of the fall season. The temperatures are usually hot throughout these months. 

Using a lawn mower in these seasons can cause the engine to overheat. Besides, when the lawn mower is in use, the friction of the internal parts of the machinery can also lead to damage through overheating.

A right oil acts as a lubricant that helps the proper functioning of intricate parts of the motor. It significantly reduces the friction between the parts, which in turn cools it down to avoid overheating the lawn mower. 

Selecting the wrong oil for the lawn mower can clog up internal motor parts, causing them to move slower or get entirely jammed. 

How do I choose the right oil for my lawn Mower?

The brand does not matter

The lawn mower manual is likely to recommend that you should use either their brand of oil or the one they have suggested. However, in the long run, it does not matter which brand you use, so long as the oil you are using is formulated specifically for use in a lawn mower. 

The same is the case with generic oil versus a brand name oil. You will find it surprising to learn that generic oils are often the right oil and provide you with the same quality for a comparatively lower price.

Choose the correct viscosity

The Society of Automotive Engineers has categorized motor oils that indicate the viscosity as well as the temperature in which they can be used. This connotation is called SAE and is printed on every motor oil bottle. It also indicates whether the oil is synthetic or not. This helps you to decide which is the right oil for your lawn mower.

The right oil will have the right viscosity of the oil is what helps the lawn mower engine stay thoroughly lubricated, even when the temperature fluctuates. You must take note that one viscosity does not deliver the same performance as another, which is why there are two common viscosities generally used in lawn mower engines.

The first viscosity, SAE 30, is ideal to use during the regular mowing season. However, this viscosity can often tend to result in hard starting as the temperature begins to drop below 40°Fahrenheit. 

The second, SAE 10W-30, is more suitable for use in places where the weather is cold. It must be noted, though, that SAE 10W-30 viscosity has a higher rate of consumption and tends to and burn-off in weather above 80°Fahrenheit.

Mentioned below are various lawn mower SAE oil types to help you choose better:

SAE 30: SAE 30 oil delivers a flawless performance in warm temperatures. It is well suited for smaller engines.

SAE 10W-30: SAE 10W-30 oil is a lighter variant. It facilitates smoother starting in cold weather. It has a higher rate of consumption.

SAE 5W-30: SAE 5W-30 oil is ideal for places with a very cold temperature.

Synthetic SAE: Synthetic SAE oil is suitable for any and all temperatures. It also has a lower rate of consumption.

Vanguard W-50: Vanguard W-50 is an innovative lawn mower oil that is suitable for use in all temperatures. This lawn mower oil is ideal for commercial use, such as landscaping businesses.

Oils listed above are classified as SF, SH, SJ, and SG use or higher.

Oil additives

There are many oil additives available in the market. However, avoid the temptation of adding them to the lawn mower. The additives and detergents are not healthy for the small engine of your lawn mower. These additives are suitable only in large lawn mower engines.

Frequently Asked Questions Related to Lawn Mower Oil

It will serve you well to hold on to the user manual of the lawn mower. You are likely to require it for reference for the upkeep of the lawn mower. The user manual will have information on how regularly you should change the oil. This information may vary for every lawn mower depending on the size and power capacity.

If you operate the lawn mower in an environment that is dusty or dry and windy (dry wind is likely to carry fine dust with it), then you must change the oil a little more often than mentioned in the user manual. If the lawn mower is not well oiled, dust can settle in between the components causing clogs and jams.

If you don’t have the user manual, then you must change the oil before spring when the mowing season begins. Changing the oil in the lawn mower prior to the mowing season is the longest the lawn mower should have to go between oil changes.

What should I bear in mind when I change the oil?

Disconnect the spark plug and empty the gas

When you want to change oil, there are a few important steps to follow. As trivial as these steps may be, not following them can cause a potential safety hazard. Always remember to first disconnect the spark plug. Disconnecting the spark plug prevents the lawn mower from starting by accident when you are changing the oil.

When you change the oil in the lawn mower, you need to tilt it. Tilting the lawn mower allows the previously filled in oil to drain out. However, in an attempt to drain the oil, there is a chance that the gasoline from the fuel tank spills out as well. 

Gas is a highly flammable substance, and its spillage can pose a safety threat. Besides, gasoline is a limited and expensive resource. It is wise not to waste it. You can time the oil change close to when the fuel tank is nearly empty. If it is not possible to wait till the fuel tank is empty, then the next best alternative is to siphon the gasoline out.


Newer models of lawn mowers feature a drain plug to drain out the oil. This facilitates the easy removal of oil. However, if your lawn mower does not have a drain plug, then you will need to tilt the lawn mower to drain it out. Oil is generally thick and sticky. It takes a long time to drain the oil of this viscosity. One simple tip to speed up this process is to run the lawn mower for a minute or two prior to changing the oil. Running the lawn mower helps warm up the oil. Warm oil tends to be less thick and flows out easily.

Note: You may want to consider spreading some kitchen towels or old newspapers or an old rag or any other absorbent cloth or paper on the floor to get hold of the oil drops missed by the oil pan or the drops splattered from the pan. It is best not to let even a single drop of oil spill on the floor, as it is combustible and slippery.

How much oil will I need if I have a small lawn mower?

Just like automobile engines, even lawn mower engines require periodic oil changes to stay in top shape and maintain a long engine life. For small lawn mowers, oil changes are even more critical as most models don’t have oil filters that help screen out contaminants released by the engine. 

Small lawn mower engines need less than a quart oil bottle to adequately fill the crankcase.

What can happen if I overfill oil in the crankcase?

Too much oil is not as bad as having low or no oil. That said, even too much right oil in the crankcase comes with its own set of problems. The lawn mower engine will need to generate more heat than it usually does.

Too much of the right oil can lead to excessive overheating of the engine. Furthermore, filling in too much oil might affect the motion of the crankcase negatively. If there is excess oil, it can lead to a slow-starting of the engine, which can be frustrating. 

It is always a good idea to pour in the oil as slowly as possible and keep checking the level of oil using a dipstick after pouring in a few ounces.


There is no best oil on the market. You must choose oil for your lawn mower based on a variety of factors. As discussed earlier, the temperature of the place you live in will determine the viscosity of the oil you should select. 

It is best not to pay heed to the brand names as you can get oil that is better suited for your lawn mower for less money. 

Oil changes, as recommended by the manufacturer, are essential as they help the engine stay in top shape and also increase the productive years of the engine. 

When performing an oil change or any other maintenance work, it is best to exercise safety precautions.

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