To change the oil on your lawn mower, warm the engine briefly, locate and open the drain plug (or tilt the mower if no plug exists), drain the old oil completely, replace the oil filter if your model has one, refill with the manufacturer-recommended oil type and amount listed in your owner’s manual, check the oil level with the dipstick, and dispose of used oil responsibly at a recycling facility.
Before You Start
Before you begin, it is important to understand the differences between mower types and gather the correct information and supplies. Proper preparation makes the job easier and prevents costly mistakes.
Is Your Mower a Walk-Behind or Riding Model?
Walk-behind mowers typically have smaller engines and may lack an oil filter, relying on simple splash lubrication. Riding mowers have larger engines, often include an oil filter, and hold more oil. The basic procedure is similar, but the exact steps, drain plug location, and oil capacity differ. Knowing your mower type helps you anticipate what you will need and where to look for components.
Where Do I Find the Correct Oil Type and Capacity?
The most reliable source of information is your owner’s manual, which lists the exact oil type, viscosity, and capacity for your specific model. If you do not have the manual, many manufacturers publish specifications online. You can also check the label near the oil fill cap or dipstick, which often indicates the recommended oil weight. Never guess, as using the wrong oil or overfilling can damage the engine.
Warming and Draining the Engine
Draining the old oil is the core of the oil change. Warming the engine first and using the correct technique ensures the oil is removed completely and safely.
Why Should I Warm the Engine First?
Warming the engine thins the oil, reducing its viscosity so it flows out faster and more completely. Run the mower for about five minutes, then turn it off and let it cool slightly. Warm oil also carries more suspended contaminants, leaving the engine cleaner. Avoid draining oil that is hot enough to cause burns; a warm but not scalding temperature is ideal.
How Do I Access the Drain Plug or Tilt Drain Point?
Most mowers have a drain plug at the bottom of the engine or oil pan, accessible from underneath. On riding mowers, you may need to raise the deck or access a cutout in the frame. If your mower has no drain plug, you can drain through the oil fill tube by tilting the mower. Tilt it with the air filter and carburetor facing up to prevent oil and fuel from leaking into them, and hold it steady over a drain pan until the oil stops flowing.
What Container Should I Use for Old Oil?
Use a sturdy drain pan or catch container large enough to hold the full oil capacity of your mower. A pan with a spout or a wide, shallow design makes pouring the used oil into a disposal container easier. Avoid using containers that may tip over or leak. Once drained, transfer the oil to a sealed container for proper disposal.
Oil Filter Replacement
If your mower is equipped with an oil filter, replacing it during an oil change keeps the new oil clean and protects the engine from wear.
Does My Mower Have a Replaceable Oil Filter?
Many riding mowers and larger engines include a spin-on oil filter, while most small walk-behind engines do not. Check your owner’s manual or inspect the engine for a cylindrical filter housing near the oil pan. If your mower has no filter, you can skip this step, but be sure to drain the old oil completely to remove contaminants.
How Do I Remove and Install a New Filter?
After draining the oil, use an oil filter wrench to loosen the old filter by turning it counterclockwise, then remove it by hand. Apply a light coat of fresh oil to the rubber gasket on the new filter, screw it on by hand until snug, and tighten it an additional three-quarters of a turn. Do not over-tighten, as this can damage the gasket and cause leaks. Wipe away any spilled oil before refilling.
Adding Fresh Oil
Refilling with the correct type and amount of oil is critical for engine performance. Adding too little or too much can cause serious problems.
How Much Oil Does My Mower Need?
The oil capacity varies by model and is listed in your owner’s manual. Small walk-behind mowers typically hold about 18 to 20 ounces, while riding mowers may hold 1.5 quarts or more. Always measure carefully and add oil gradually. Do not rely on estimates; check the manual or the label near the fill cap for the exact capacity.
What Oil Weight Should I Use?
Most small engines use SAE 30 for warmer temperatures or 10W-30 for a broader temperature range. Some modern engines may recommend a synthetic blend or a specific multi-grade oil. The correct weight depends on your engine and the climate in which you operate. Check your owner’s manual for the manufacturer’s recommendation, and use a high-quality oil that meets the specified standards.
How Do I Verify the Correct Level?
After adding oil, check the level with the dipstick. Insert the dipstick fully without screwing it in, then remove it and read the level. The oil should sit between the minimum and maximum marks. Add small amounts at a time, rechecking after each addition to avoid overfilling. Overfilling can cause foaming, leaks, and engine damage, so take your time.
Safe Disposal
Used engine oil is hazardous and must be handled responsibly. Proper disposal protects the environment and complies with the law.
Where Can I Recycle or Dispose of Used Motor Oil?
Many auto parts stores, service stations, and recycling centers accept used motor oil free of charge. Some municipalities offer designated drop-off sites or curbside collection programs. Store the used oil in a sealed, leak-proof container, and never mix it with other fluids such as antifreeze or solvents. Check with local facilities for their specific requirements, and never pour oil down a drain, onto the ground, or into the trash.
