When and How to Change Oil In a Lawn Mower

Do you look for any excuse to put off lawn mower maintenance? I get it — keeping up with oil changes isn’t exactly fun. But skipping them can lead to bigger headaches down the road. Engine damage, costly repairs and poor performance all await a neglected lawnmower. You may also find yourself shopping for a new one sooner than later.

To make sure you’re getting the best performance and preserving the lifespan of the small engine, you have to perform some regular maintenance, including oil changes. Ahead find easy-to-follow steps to change the oil in your lawnmower with tips from seasoned small engine repair experts.

Why Change the Oil in Your Lawn Mower?

Just like a car, lawn mowers need oil changes too. Engines require clean, fresh oil in the right amounts to lubricate moving parts and run properly. Exposure to high engine running temperatures, contaminants and moisture causes motor oil to break down over time, reducing its lubricating abilities. Eventually, the oil stops being effective and needs to be removed then replaced with fresh oil.

When To Change the Oil In Your Lawn Mower

The type of lawn mower you are using, and how often, will determine when to change or add fresh oil to the mower.

• New mower engine: Change and replace the oil soon after its first use or roughly five hours of run time. “The moving parts are just breaking in, so changing the oil cleans out anything that might come loose during that time,” Rick Lemelin from Get Your Fix Small Engine Repair says.
• Existing push mowers: Change and replace the oil at least once a season or for every 50 hours of run time.
• Existing riding mowers: Change and replace the oil at least once a season or for every 100 hours of run time.

How To Choose the Right Lawn Mower Oil for Your Mower

Using the right type of oil is important to getting the best performance from your engine. You’ll want to use a motor oil meant for small engines, like 5W-30 or 10W-30. This single-weight oil is ideal for smaller engines that only operate in above-freezing temperatures. Multi-weight oil used in automobiles will wear down a small engine, so it is not advised.

How much does lawn mower oil cost?

Typically sold by the quart, lawn mower oil costs between $4 to $12, depending on the kind you’re purchasing.

How To Change the Oil In Your Lawn Mower

Set aside about 30 minutes to complete this maintenance task.

Push Mower

First, empty out the old oil, then replace it with new oil.

1. Seal the gas tank: Seal the gas tank by removing the gas cap and covering the opening with a plastic bag. Screw the cap back on over the plastic bag.
2. Empty out the old oil: Remove the dipstick from the oil filler tube and tip the mower to drain the oil. Pour the used oil into a plastic milk jug or similar container and recycle it.
3. Refill with clean oil: Refill the engine with clean oil. Most engines require about 20 ozs. (5/8 quart), but double-check the manufacturer’s instructions. Insert the dipstick and check the oil level. Add oil if needed, but don’t overfill.
4. Alternate oil draining method: Unscrew the plug located on the bottom of the engine and allow the oil to drain into a pan. Lower the mower down on its wheels to make sure all the oil drains. Replace the plug. Then, set the mower on a level surface and fill the engine with clean oil through the filler hole near the base of the engine.

Riding Mower

Follow the same general steps as you would a push mower. “It’s really the same principle,” Mike Czepiel from M& M Small Engine Repair says. “It just takes a lot more oil.” Refer to your owner’s manual or online tutorials for the location of the necessary parts to complete the job.

Lawn Mower Maintenance Tips

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Perform these tasks each season to keep your mower running strong.

• Change the oil: Make it part of your winterization process in the fall, or do it first thing each spring.
• Sharpen and balance blades: “Blades should be sharpened two to three times a year,” Lemelin says, “and balanced.”
• Change the fuel filter: The fuel filter prevent debris from getting into your engine fuel system and clogging up important moving parts. Replace it once a season.
• Keep debris out of your portable fuel container: Close portable fuel containers, or gas cans, when not in use and wipe down regularly.”This keeps any of that dirt from getting into the gas,” Lemelin says.
• Change the air cleaner: There are two parts to most lawn mower air cleaners: a paper filter and a re-usable sponge pre-filter. Replace the paper filter each season, and clean the pre-filter. “Take it off and wash it with soapy water,” Lemelin says.
• Clean the mower deck: Mowing wet grass can cause grass to build up underneath the lawnmower, which can affect its performance. Check and clean the underside and top of the mower deck regularly through the season.
• Check the belts: Visually inspect belts at least once a season and replace any loose, worn or fraying belts. Most mowers have two belts, from the motor to the transmission and from the motor to the blades.

FAQ

Is expensive lawn mower oil better than cheap lawn mower oil?

Both pros agree that there’s no noticeable difference between cheaper oil and more expensive products.

Czepiel recommends using a semi-blend oil (part synthetic and part conventional oil). “It’s a little more expensive, but it’s cheaper than a new engine,” he says.

Does it matter what oil I use in my lawn mower?

You should use 5 or 10W-30 in your lawnmower, or motor oil specifically labeled for use with small engines. Automotive oil is not recommended.

About the Experts

• Mike Czepiel is the owner of M & M Small Engine Repair in West Springfield, Massachusetts. He has been fixing and servicing lawn mowers, snowblowers, generators and other small engines for over 30 years.
• Rick Lemelin is the owner of Get Your Fix small engine repair in Chicopee, Massachusetts. He has over twenty years of experience fixing and repairing small engines and autos.