How To Change Oil In Lawn Mower?

Gasoline powered lawnmowers need oil to help lubricate key moving parts of the internal combustion engine. This includes the pistons and the cylinder walls. Without oil, the heat generated by the internal combustion process would eventually cause the engine to seize up. In the short-term, this could stop the engine until it cools down. In the long-term, it could score the cylinder walls and cause permanent damage to the engine block itself.

With a two-cycle lawnmower engine, you simply mix a special type of two-cycle oil with the gasoline every time you refill the tank. The downside of this engine is that it tends to be noisy, smokey, and not as fuel-efficient. This has driven a lot of lawnmower manufacturers to sell push and riding lawnmowers with four-stroke engines.

What Do I Need To Change The Oil In My Walk-Behind Lawn Mower?

With a walk-behind lawnmower changing the oil is relatively simple. You only need some basic tools and equipment such as:

  • A Drain Pan (Sold at Automotive Stores)
  • Replacement Motor Oil (According To Manufacturer’s Specs)
  • A Replacement Oil Filter
  • Gloves
  • Paper Towels Or Clean Shop Rags
  • A Funnel
  • Pliers Or Socket Wrench For The Oil Cap
  • An Oil Filter Wrench Or Pipe Wrench
  • A big sheet of cardboard to catch any oil drips and prevent stains on your driveway or oil soaking into your lawn.


Do I Need A Special Jack To Change The Oil In A Riding Lawn Mower?

This depends on the size of your lawnmower, and your personal ingenuity. Professional lawn care companies will usually invest in a heavy-duty lift jack to safely raise and lower the major investment of a zero-turn or a high-value riding lawnmower.

If you have a little bit of a berm, an easy to access curb, or some simple portable ramps, you should be able to position a consumer-grade riding lawnmower for easy access to the underneath oil pan.

Step By Step Instructions For Changing Lawn Mower Oil

Gather all your equipment and position your lawnmower to make sure no oil will escape into the surrounding environment. It’s also a good idea to put on some old clothes, keep some work or latex gloves nearby and make sure to put on eye protection. Even a tiny oil spatter in your eyes can be a major problem.


Step 1: Turn the lawnmower on and let it run for a minute to gently warm the oil. Do not let it run for more than 90 seconds or the engine parts might get hot.

Step 2: Carefully disconnect the spark-plug wire to prevent accidental ignition while changing the lawnmower’s oil.

Step 3: Use clean paper towels or fresh shop rags to wipe away any old dirt and oil from the oil reservoir and dipstick.
Step 4: Use a wrench or pliers to loosen the drain plug and drain the oil into the portable drip pan.
Step 5: Use an oil filter wrench or a pipe wrench to remove the old oil filter.
Step 6: Dab a little clean oil on your finger and wipe oil along the seam of the oil filter.
Step 7: Use the oil filter or pipe wrench to tighten the new oil filter into place.
Step 8: Refill the engine oil reservoir by placing the funnel in place. Hold it there while you carefully pour the new engine oil in. Stop periodically to let the oil settle, and double-check to make sure that you aren’t overfilling the reservoir.
Step 9: Carefully clean up any oil spots. Then take the old oil filter and used engine oil to the nearest oil recycling center.

Frequently Asked Questions

Can I Use Any Type Of Oil In My Lawn Mower?

Ideally, you want to use the same type of oil that the manufacturer recommends. This is specially formulated to deal with the heat the engine produces. If you use a different type of motor oil than they recommend the mower might still run for a while, but you could risk damage to the motor due to changes in viscosity and thermal breakdown.

If you find yourself in a pinch, where your lawnmower’s oil is very low and you don’t have time to run to an automotive store just to continue mowing your lawn, you can usually get by with standard SAE 10W 30 motor oil. This is the most common type of motor oil used in cars and trucks. Still, if your lawnmower isn’t specifically rated to use 10W 30, you should plan on doing a full oil change before the next time you cut the grass.

Is It Bad If My Lawn Mower Smokes After Changing The Oil?

A little bit of smoke after an oil change usually isn’t something to be alarmed by a little smoke. Especially if you accidentally spilled a drop or two on the lawnmower’s engine block while you were refilling it. Beyond that, a little blue smoke in the exhaust should clear up within a minute or two after starting up the engine.

How Often Should I Change The Oil In My Lawn Mower?

Professional lawn care companies who run their commercial-grade lawnmowers on an almost daily basis will change their lawnmower oil every few weeks or about 50 hours running time. If you are just mowing a residential lawn once a week or so, you can usually get by with a seasonal oil change every spring or at least the end of the season.

Do You Need To Change The Oil In A Four Stroke Lawn Mower Engine?

In the past, you needed to change the oil in all four-stroke engines. Just how often depended on the make, model, and overall use. Some people merely changed lawnmower oil every spring. Though a professional lawn care company may have to do it more often. When in down check your owner’s manual to see what the manufacturer recommends.

It’s also worth noting that in recent years lawnmower manufacturers have started to offer “Check & Fill” oil systems. These newer models are specially engineered to not need oil changes at all. You merely check the oil level every week or two and top it up to the proper level.

These systems are relatively new and there are some people who debate their long-term effectiveness as the years go on. At this time, the majority of four-stroke lawnmowers need periodic oil changes.


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