Knowing how to change the oil in a lawn mower is important for keeping your machine running properly. There are three common methods for changing the oil: using the drain plug, tilting your mower to its side, or using an oil extractor.
Oil lubricates your lawn mower’s internal parts, reducing friction and wear. It also helps prevent overheating and corrosion, which can shorten your mower’s lifespan. Fresh oil guarantees smooth operation, allowing your mower to perform at its best throughout the entire season.
In this guide, I’ll explain the best way to change your mower’s oil. It’s recommended to change your push mower’s oil after 50 hours of use and your riding mower’s oil after 100 hours.
| Skill level: Beginner Estimated time: 15 to 30 minutes Cost: $11 and $80, depending on whether you need filters or if you buy an oil extractor |
What you’ll need
- New oil as specified by the manufacturer
- Socket set or wrench (if using a drain plug)
- Oil drain pan
- Funnel
- Rags or paper towels
- Gloves
- Oil extractor (optional)
- Oil filter (if your mower has one)
- Cardboard or plastic sheeting to protect the ground from spills
Step 1: Prepare your mower
Start by placing your lawn mower on a flat surface to keep it stable. If you have cardboard, slide it under your mower to catch drips — I like to do this to keep things neat, but it’s not a must. Wearing gloves is also a good idea to keep your hands clean and protected.
Run your mower’s engine for 5 to 10 minutes to warm the oil. This helps it flow easily and removes debris when draining. Once done, turn off the engine and let it cool down for a couple of minutes so you don’t burn yourself.
Next, for safety purposes, disconnect the spark plug wire or remove the battery to prevent any accidental starts. Batteries are generally only in gas-powered riding lawn mowers.
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Step 2: Drain the oil
Now, it’s time to drain the oil. The method you use will depend on your mower type and the tools you have. You can do this in three ways: using the drain plug, tilting the mower, or using an oil extractor.
Depending on your mower’s design, the oil drain plug is commonly found beneath the mower deck or at the bottom of the engine block, often near the crankshaft. Riding mowers almost always have an oil drain plug, while most newer push mowers do not. However, some older push mowers may still have a drain plug located under the deck.
If your mower doesn’t have a drain plug, locate the oil filler cap. This cap is often marked with an oil can symbol. Before opening the cap, wipe around it with a clean cloth to make sure no dirt falls inside the engine.
Use the drain plug
Best for: Riding mowers and walk-behind mowers with a drain plug.
- Place a drain pan under the mower to catch the oil.
- Use a wrench to loosen and remove the drain plug.
- Let the oil drain completely into the pan.
- Wipe off any excess oil around the plug area.
- Reinstall and tighten the plug securely.
- Wipe up spills and transfer the used oil into a sealed container.
Tilting the mower
Best for: Push mowers without a drain plug.
- Make sure the air filter and carburetor are facing up when you tip the mower, these are usually located on the side of the engine opposite the oil fill cap. This step prevents oil from getting into them.
- Position the drain pan near the dipstick tube.
- Remove the oil plug or dipstick, using a wrench if needed.
- Tilt the mower so the oil drains directly into the pan.
- Let it drain completely, then set the mower back on level ground.
- Wipe up any spills and transfer the used oil into a sealed container.
Using an oil extractor
Best for: Any type of mower.
- Remove the dipstick.
- Insert the extractor tube into the oil fill hole, making sure it reaches the bottom of the oil reservoir.
- Pump out the old oil. Either manually or with an electric extractor.
- Transfer the used oil into a sealed container.
Important note: Never dump used oil on the ground, in the trash, down the drain, or into storm sewers. This is illegal in most places and harmful to the environment. Instead, store your used oil in a clean, labeled container, and once it’s full, take it to a recycling location. Many auto parts stores, municipal waste collection centers, and gas stations also accept used oil.
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Step 3: Add new oil
With the old oil removed, the next step is filling your mower with new oil. First, check your mower’s manual for the recommended oil type and amount. You can also find this information on a label near the engine or oil cap. If you can’t find the manual or a label on the mower, you can use this guide based on the type of engine and climate:
| Oil Type | Best for | Characteristics |
| SAE 30 | Small engines, push mowers | This oil is used in warm weather (40 degrees and above) |
| 10W-30 | Push mowers, riding mowers | Good for warm and cold weather |
| Synthetic 5W-30 | High-performance mowers | Performs in all temperatures |
| 15W-50 | Heavy-duty or racing mowers | Hot climates and heavy workloads |
Once you’ve identified the correct oil from the chart above, place a funnel into the oil fill opening. Slowly pour the recommended amount of oil. Push mowers typically take 15 to 20 ounces, while riding mowers need 48 to 64 ounces.
If you’re unsure how much oil you’ve added, you and easily check with the dipstick: Remove it and wipe it clean, insert it again, and pull it out. The oil mark on the dipstick should be between the low and full levels. Add more if needed and recheck with the dipstick.
Finally, don’t overfill. Too much oil can cause smoking, leaks, or engine damage.
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Step 4: Change the oil filter
If your lawn mower has an oil filter, it’s recommended to replace it whenever you change the oil. Oil filters are commonly found on riding mowers and some high-end push mowers. Push mowers with small engines usually don’t have an oil filter.
First, you’ll need to locate the oil filter, which is usually near the engine on riding mowers or close to the oil fill cap on push mowers. Place a drain pan underneath, as some oil may spill during removal.
Next, turn the filter counterclockwise to unscrew it. If it’s stuck, use an oil filter wrench for extra grip. Apply a small amount of fresh oil to the rubber gasket. This helps create a proper seal and makes removal easier next time.
Finally, screw in the new filter by turning it clockwise until snug but don’t overtighten, as this can damage the gasket.
My tip: Some mowers recommend pre-filling the filter with oil before installation to prevent dry starts, so check if this applies to your model.
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Step 5: Finish up
Make sure the oil filler cap is securely tightened, then reconnect the spark plug wire or reinstall the battery if you removed it earlier.
Then, start the engine and let it run for 2 or 3 minutes. This helps the new oil circulate through the engine and ensures everything works properly. After shutting off the mower, check for any leaks around the drain plug and oil filter.
Finally, recheck the oil level using the dipstick. Running the engine may cause the oil level to drop a little. If needed, add a little more oil to bring it to the full mark.
Read more: How Often Should You Sharpen Lawn Mower Blades?
Troubleshooting common oil issues
If your mower exhibits issues like excessive smoke, oil leaks, or it simply won’t start after an oil change, don’t worry. Most problems have solutions. Use the chart below to diagnose common oil problems.
| Problem | Solution |
| Low oil level: Due to normal engine consumption, leaks, or forgetting to refill after an oil change. | Always check the oil level before each use and add more oil if it’s low. Inspect the mower for leaks and replace any faulty gaskets or seals. |
| Overfilled oil: Too much oil added during a refill or checked on an uneven surface, leading to inaccurate readings. | Drain the excess oil using the drain plug, an oil extractor, or tilting the mower. |
| Cloudy oil: Water contamination from rain, moisture, or mowing wet grass. | Drain and replace the oil to prevent engine damage. Store the mower in a dry place and cover it when not in use. Check the oil cap for cracks or looseness. |
| Dirty oil: Oil darkens from heat, dirt, or overdue changes; a clogged air filter can also contribute. | Change the oil at least once per season or every 50-100 hours of operation. Check the air filter and replace it if it’s dirty or clogged. |
| Smoke from the engine: Excess oil or incorrect tipping allows oil to enter the carburetor and burn. | Check the oil level and drain any excess. If you recently tipped the mower, always tilt it with the carburetor side up. If smoking continues, inspect the engine for wear or damage. |
| Oil leaking: Loose drain plug, damaged gaskets, or overfilled oil causing pressure buildup. | Tighten the oil drain plug and check for worn gaskets or seals. If the leak persists, inspect the engine and ensure the oil level isn’t too high. |
| Mower won’t start: Oil level is off, spark plug is fouled with oil, or the wrong oil type was used. | Check and adjust the oil level. Remove and inspect the spark plug for oil residue. Clean or replace it if needed. Make sure you’re using the manufacturer-recommended oil type. |
| Mower runs rough or loses power: Incorrect oil type, dirty air filter, or oil-contaminated carburetor or spark plug. | Ensure you’re using the correct oil type. If the air filter is oily or dirty, clean or replace it to restore airflow. Check the spark plug and clean or replace it if there’s oil buildup. |
Read more: How to Clean a Lawn Mower Deck
FAQ about lawn mower oil
For push mowers, change the oil every 50 hours or at least once per season. Riding mowers need an oil change every 100 hours or once per season. In hot weather or dirty conditions, you might need to do it more often.
Always check your mower’s manual for the right oil type. Some common options are SAE 30, 10W-30, but not all mowers use the same kind. Avoid car oil. It’s not designed for small engines.
Many manufacturers recommend changing the air filter with every oil change to keep the engine running smoothly and prevent dirt from getting inside. A clean air filter helps with better airflow, fuel efficiency, and overall performance. Always refer to your mower’s manual for exact guidelines.
Find a lawn care pro in your area
Regular lawn mower oil changes ensure your lawn mower runs efficiently and lasts for years. A well-maintained mower makes yard work easier. If you ever need help mowing your lawn, fertilizing, or controlling weeds, LawnLove can connect you with a professional in your area.
Sources:
- “Mower Maintenance.” University of Illinois Extension
Main Photo Credit: PLG | Adobe Stock
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