What Grade Oil Should I Use in My Lawn Mower? If you’re wondering what oil you should use for your lawn mower, you’re not alone. Choosing the correct oil is one of the easiest ways to keep your lawn mower running smoothly, improve engine life and reduce the risk of costly repairs. Whether you have a petrol lawn mower, ride-on mower or other garden machinery, using the correct oil grade ensures your engine will run as it should and perform at its best. In this guide, we’ll explain everything you need to know about petrol lawn mower oil, the different oil grades available, and how to choose the right one for your mower. Why Does Lawn Mower Oil Matter? Engine oil has one job, and it’s a very important one. Oil provides lubrication to the moving parts inside the engine, reducing friction and protecting against overheating. Without the right engine oil for your lawn mower, the internal components will wear out a lot quicker. This leads to poor performance and may cause complete engine failure. Fresh oil will also: Protect against corrosion Keep the engine running cooler Help carry away contaminants Improve fuel efficiency Extend engine life It’s also important to change your oil regularly. What Type Of Oil Should I Use In My Lawn Mower? There are three main factors that determine what oil you should put in your lawn mower. Manufacturer recommendation The outside temperature Engine type Your owner’s manual should always be your first port of call as manufacturers usually specify which oils are compatible with their mowers. Oil recommendations vary depending on how and where you use your mower. SAE 30 SAE 30 is one of the most common oils used in lawn mowers. It’s a single grade oil designed for use in warmer temperatures. In the UK, many people use SAE 30 throughout spring and summer. It’s best for: Most four-stroke petrol lawn mowers Consistent temperatures above 10°C Regular domestic use 10W-30 10W-30 is better if you’re using your mower across a wider range of temperatures. Multi-grade oils flow more freely during cold-starts while still providing protection when the engine is warm. It’s best for: Variable UK weather Mowers used year-round Many modern petrol engines 5W-30 5W-30 is a thinner oil designed to start more easily in cold temperatures. It’s commonly used in northern European countries or colder US states. While it’s not often required for domestic mowers in the UK, some manufacturers do specify it for particular engines. Check your handbook before using 5W-30. Can I Use Car Engine Oil In My Lawn Mower? Many people ask whether standard motor oil is suitable for a lawn mower. In most cases yes. Lawn mower engines generally use the same type of detergent engine oil found in cars, provided it’s the correct viscosity grade specified by the manufacturer. However, avoid assuming that every oil is suitable. Using an oil with the wrong viscosity can effect lubrication, increase engine wear and even cause overheating. Never use motor oil with a different viscosity than recommended in your owner’s manual. Some mowers may require specific oil types for improved protection, and using the wrong viscosity can lead to: Decreased lubrication Engine wear Overheating Always double-check that you’re using the correct oil for your lawn mower. Two Stroke Or Four Stroke? Knowing whether you have a two stroke or four stroke engine is important when buying oil. Four Stroke Engines Most modern petrol lawn mowers use four stroke engines. Four stroke engines have separate compartments for petrol and engine oil, meaning you simply top up or replace the oil during servicing. Two Stroke Engines Some older mower models and handheld garden machines use two stroke engines. These require a specific two-stroke oil mixed directly with petrol at the manufacturer’s recommended ratio. Never use standard four-stroke engine oil in a two-stroke mower. When To Change Your Lawn Mower Oil Even the best petrol lawn mower oil loses its effectiveness over time. As a rule of thumb, try to replace your lawn mower oil: Every 25 to 50 hours of use (for walk-behind mowers) At least once per mowing season Before storing the mower for winter if the oil is dirty Old oil collects dirt, carbon and moisture from the engine, reducing its ability to protect it. If you use your lawn mower frequently or professionally, consider changing the oil more often. Top Tips for Changing Your Lawn Mower Oil Look after your lawn mower with these easy tips: Check your owner’s manual first Match your oil grade to local weather conditions Choose a high-quality oil from a reputable brand Don’t overfill the engine Check oil levels every few uses Taking a few moments to check your oil will save you from expensive repairs. Find the Right Oil and Garden Machinery at Mowshop Whether your servicing an old mower or buying a brand new one, using the right oil is essential to ensure your mower is performing at its peak. We stock petrol lawn mowers, ride on mowers and garden equipment from leading brands, helping homeowners and professionals keep their gardens looking their best. If you’re not sure what oil your mower needs, our experts are on hand to point you in the right direction, so you can get back to cutting with confidence. Correct oil is just one of the simple steps you can take to look after your lawn mower, and ensure you get the longest life, optimal performance and best reliability from your investment.
