What Kind of Oil Should I Put in my Lawn Mower?

What Kind of Oil Should I Put in my Lawn Mower?

A question we commonly receive is “what type of oil should I put in my lawn mower?” In this article, we’ll go over the different types, what the numbers actually mean, and compare conventional to synthetic oils.  

Changing the Oil 

The internal combustion engine in your lawn mower needs oil in order to run. Without it, your engine would overheat and seize up, as the oil helps to lubricate all the moving parts. Dirty oil will wear the engine faster, decreasing its lifespan. Changing the oil in your lawn mower is an important part of its routine maintenance, and should be done at least once per season, or every 50 hours of use. Proper oil changes can increase your mowers performance and add years to its life, which will save you money in the long run.  

Changing Lawn Mower Oil

How to Read the Labels  

An SAE number is a code used to classify oil by viscosity, which was developed by the Society of Automotive Engineers. Viscosity is a measure of a fluid’s resistance to flow, sometimes referred to as the “thickness” of a liquid. The lower the number the easier the liquid flows. Motor oils have a rating between 5 and 50. Temperature can make a difference in a liquid’s viscosity, which is why the different oils have ratings for winter, indicated by the “W”. Oils that are multi-rated (for example, 10W-30) can be used in both summer and winter temperatures since the oil won’t thicken in the cooler temperatures due to additives.   

Reading a Lawn Mower Oil Label

Different Types of Oil 

So, what type of oil should you use for your lawn mower? One factor to keep in mind is the climate for where you’re located. Different oils work best at different temperatures, and they won’t all be right for your equipment. Always be sure to check your owner’s manual for the manufacturer’s recommendation for your mower. We’ve put together this guide to help you choose between some common types of oil. 

SAE-30 Small Engine Oil 

This is the most commonly used grade of oil for lawn mowers since it is ideal for temperatures between 40 to 100 degrees Fahrenheit (4 – 37C). If it’s cooler than 40 degrees outside, you probably don’t need to be mowing your lawn. Overall, this is your best bet for an inexpensive oil you can use in your lawn mower from spring through to fall.  

SAE 10W-30 

This oil has a wider range of temperatures that it will work for, from 0 degrees to 100 degrees Fahrenheit (-17 – 37C). Because it can handle cooler temperatures, this type of oil can also be used in other small engines like snow blowers. If used when temperatures are above 80 degrees, you may find your mower increases the oil consumption. 

SAE 5W-30 

This grade of oil performs best in temperatures below 40 degrees Fahrenheit (4C). So, it is ideal for your snowblower, but not a good choice for your lawn mower.  

Synthetic SAE 5W-30 

The synthetic version of 5W-30 has a wide range of temperatures it can be used in, from –20 to 120 degrees Fahrenheit (-28 – 48C) so it works year-round for your small engines. It improves the starting of your engine, and reduces oil consumption, but it is more expensive to purchase.  

Synthetic SAE 15W-50 

This oil also has a high temperature range, from 20 to 130 degrees Fahrenheit (-6 – 54C) but performs best in higher temperatures. It is typically used for commercial lawn cutting equipment.  

Conventional Versus Synthetic Oil

Conventional Oil vs Synthetic Oil 

Is conventional oil or synthetic oil better for your engine? Generally speaking, conventional oil will work just fine in your small engine. So long as you are using the oil under proper conditions, it will provide the protection and lubrication your mower needs at an affordable price. Synthetic oil however offers more protection, at a wider range of temperatures, but that comes with a higher price tag. The synthetic oil does collect more dirt, so when changing the oil these particles will be removed from your mower. This can lead to better performance overall. Whichever option you choose, it’s important to check and top up the oil levels throughout the mowing season, and to change it out completely after approximately 50 hours of run time.  

Lawn Mower Cutting Grass

A well maintained and cared for lawn mower will perform the most efficiently, saving you money in the long run. If you need genuine OEM replacement parts for your lawn equipment, you can find them by searching for your model number on eReplacementParts.com. Be sure to follow along and subscribe to our YouTube channel so you don’t miss any tips!  


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