draining oil on a lawn mower

How To Change Lawn Mower Oil And Which Oil To Use

You should be changing the oil in your lawnmower’s engine at least once a year. Frequent changes are recommended if you mow often or if the engine is old. You can check the oil on your lawnmower’s dipstick to see if you are due for a change. It should look translucent orange-brown. If the oil has gone black, it is time for a change.

When To Change The Oil?

When first breaking in a new lawnmower, you should be ready to change the oil sooner rather than later. While it depends on the instructions from your mower’s manufacturer, changing the oil after the first 5 hours of use is a good idea.

If you want to keep your mower running as smooth a possible, change the oil after about 50 hours of use. A good way to remember this is to change the oil at the beginning of each mowing season.

How to Change The Oil – Step by Step

Changing your lawnmower’s oil is a simple process that you can do yourself at home. You will need fresh oil from a supply store, as well as an oil pan, some rags, and newspapers or cardboard to protect your floor with.

1. Assemble A Workspace And Ready Your Mower

Find a good workspace. Small push mowers are often easiest to work with when elevated on a workbench or something similar.

lawn mower on a stand

A level driveway or garage floor will also do fine. For riding mowers, you will need a large space to maneuver and to raise the lawnmower up on ramps to access the underside. Wherever you are working, lay out newspaper or scrap cardboard to catch any oil drips.

Ensure you have an oil pan on hand to collect the old oil as it drains. Turn on the mower and let it run for a minute, warming up the oil and making it flow more easily.

When you are ready to begin, shut off the mower. Carefully disconnect the spark plug wire from the spark plug to prevent accidental ignitions. With a rag, clean off the fill and drain plugs and the areas surrounding them.

2. Drain Out The Old Oil

Prop up the mower so the spark plug is facing upward, in order to avoid the gas draining out. Slip the oil pan under the mower. With a socket wrench, open the oil drain plug, rotating it clockwise to open.

oil drain bolt on lawn mower 2
The oil drain plug.
draining oil on a lawn mower 2
Draining the oil.

The oil will begin draining out. When it is finished, replace the drain plug and tighten it securely. Pour the oil into a container for disposal. You can take old engine oil to the same retailer that you buy your oil from. They will dispose of it safely.

If you cannot locate the oil drain plug or the engine does not have one, then you can tip the mower to drain the oil. Pop off the dipstick cap and tip the mower onto its side—tilt it so that the spark plug is facing upwards and the dipstick tube is close to the ground. Drain onto an oil pan, replace the dipstick cap, and dispose of the old oil.

Here’s a video of the whole process.

Draining the oil by tipping the lawn mower.

Alternatively, you can use an oil vacuum pump. Watch the video below to learn how.

Change the oil by using an oil vacuum pump.

3. Swap Out Your Oil Filter

Some lawnmowers are built with an oil filter. These mean you need to change the oil less frequently as the filter clears out dirt and debris, leaving the oil purer. However, the filter itself will need replacing once in a while, at least once a year.

Find the oil filter on your mower and remove it by twisting counter-clockwise. It will unscrew, but can sometimes be stubborn. A filter wrench is an appropriate tool for this job.

Use a rag to clean off the oil filter’s rim. Check the rubber seal on the new filter, and clean it too if there is any dirt. With a little bit of fresh oil, oil the rubber seal, then screw it into the filter slot. You can tighten it by hand until the rubber seal compresses slightly, then finish it off with a few cranks of your filter wrench.

4. Fill The Engine With New Oil

Take off the oil fill plug. Some lawnmowers have two of these, but either will work for refills. Insert a funnel into the opening and add in fresh oil. The manufacturer’s instructions will specify how much oil to use. Be careful of overfilling, as engine oil is flammable.

adding oil to a lawn mower
Filling the lawn mower engine with oil.

When you get close to full, wait a minute for the oil to settle, and then use the filler plug dipstick to precisely check the oil level. Before each check, use a rag to wipe the dipstick off in order to get an accurate read. Once the engine is appropriately filled, screw the filler plug on and use a rag to clean up any oil that spilled on or nearby the lawnmower.

Clean up any oil-soaked newspaper or cardboard that you used to cover the floor, then reconnect the spark plug wire to the spark plug.

5. You’re Done!

Well done, your mower’s engine oil has been changed! Keep an eye on the oil level as you cut your lawn and check the condition of the oil regularly. Maintaining your engine oil properly will help extend your lawnmower’s lifespan and keep it working at full efficiency.

Related: How Long Should Your Lawn Mower Last & How To Make It Last Longer?

What Kind Of Oil Should You Use?

Different kinds of oil are designed to work best in different climates, based on temperature. Use oil that is well suited to your home’s climate.

  • SAE 30 is common in small lawnmowers. It works best in warm temperatures.
  • SAE 5W-30 works best in very cold temperatures.
  • SAE 10W-30 helps your engine start in the cold, but is high consumption. It works well in a variety of temperatures.
  • Vanguard 15W-50 is good for long periods of use, such as commercial lawnmowing. It works well in a variety of temperatures.
  • Synthetic SAE 5W-30 is a low consumption oil. It works well in all temperatures.

Look for oil marked as “For Service SF/SG/SH/SJ” or higher and avoid those with additives. You can also consider synthetic oil, which tends to work well at all temperatures. Using synthetic oil does not change how frequently you should change your lawnmower’s oil.

Is The Oil Changing Process The Same For Every Manufacturer?

In broad terms, yes. Most mowers use a standard array of plugs and drains. Here are the specific maintenance instructions for some of the most common lawnmower manufacturers.

Honda

Toro

Briggs & Stratton / Craftsman / Troy Bilt

Husqvarna