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How to change lawn mower oil

How to change lawn mower oil
(Image credit: Getty)

Looking for information on how to change lawn mower oil? You’re in the right place. If you have invested in one of the best gas lawn mowers, you will need to keep it running without hitches. Regular cleaning and maintenance, including changing the oil, can help it run problem-free and extend its life.

We’ll be giving you all the advice you need, however, be sure that you refer to the operator manual for your lawn mower, as they all differ slightly. If you no longer have the paper manual, you can find help on the manufacturer’s website. 

Here’s our helpful step-by-step guide on how to drain the oil from your lawn mower.

How to drain the oil from your gas lawn mower 

Just like a car, your gas mower has oil inside the engine to help the moving parts run smoothly. This oil gets dirty and degrades over time, becoming less effective, so it’s important you change it regularly. New oil looks clear with an amber color, while old oil appears black. 

How to change lawn mower oil  

Firstly, gather all the things you need; a cloth to wipe the dipstick, the fresh oil, and a flat, wide tray to collect the old oil as you drain it out (a seed tray is good for this but use an old one). At the same time, give the areas around the dipstick cap and the oil filler cap a good clean to prevent debris from getting into the new oil. 

How to change lawn mower oil

(Image credit: Getty)

How to remove the old lawn mower oil 

  • Run the mower’s engine for a few minutes to warm the oil up, then shut it down and engage the brake. This is because warm oil flows more smoothly than cold oil and it will be easier to drain 
  • Remove the oil cap and dipstick, making sure the machine is positioned over your tray to catch the old oil 
  • Take hold of the handle and tip the machine onto its side, keeping it steady and making sure you don’t tip so far that you lose your grip 
  • If you are able to, you can rest the machine onto its side with the oil dripping into the tray 
  • Leave the machine for a few minutes to be sure you have drained all the old oil 
  • Right the machine 
  • In case of an air bubble preventing all the oil from draining out, tip it again after you have righted it. This will release any air bubbles and allow you to drain every drop
  • Pour a small amount of fresh, new oil into the filler cap; remember, you must NOT fill the oil reservoir up completely. Do not overfill – the oil level should come above the ‘fill up’ and below the ‘full’ marks on your dipstick 
  • Screw the oil cap back on, then clean around the machine in case of drips  

If you have one of the best riding lawn mowers, there will be an oil draining valve on the underside of the engine (you may need to remove parts of the engine cover to access this) and you will have a drain tube supplied with the machine. This helps drain the oil without tipping the heavy machine, which could be dangerous. Make sure you set the mower’s parking brake, take out the ignition key and remove the lead from the sparkplug before starting, then remove the oil drain valve cover, fit the tube and then twist the valve to release the oil. You should also remove the dipstick cover, to prevent a vacuum from forming inside the machine that could prevent the oil from draining. 

If your machine uses an oil filter, this is a good time to change that part too. Use a ring wrench to help you remove the filter, turning counterclockwise, wipe any spilled oil from around the hole, then lubricate the thread of your new filter with clean oil before attaching it back onto the machine and doing it up tightly. 

How to change lawn mower oil

(Image credit: Getty)

How to check the oil level 

Always check the oil level before starting the mower on a firm, flat surface.

Find the oil cover – note that this is in a different place to the gas cover. It may have the word ‘oil’ on the cover, or a picture of an oil can and is usually black or yellow. 

Unscrew the cover, pull out the dipstick and wipe this on a clean cloth. Replace the dipstick in its hole, inserting it fully and doing up the cap to ensure it is in the proper position. Pull it out again and you will be able to see the oil level by looking at the dipstick. 

If the oil level is too low, add a little at a time through the oil filler cap, allowing it to settle and checking each time you add more. 

How often should you change lawn mower oil? 

Most manufacturers suggest that you change the lawn mower oil after every 25 to 50 hours of use. As many of us don’t really keep track, it may be simpler to change it at the beginning of a new mowing season. If you use the mower in very dry, dusty or hot conditions, it may need changing more often – check the level and see what colour it is using the dipstick. 

Note that when buying a gas lawn mower, the machine will usually be sold with no oil or gas in it, so you will need to add them before use. 

For some models, the manufacturer may suggest that you change the oil after you have used it for the first few hours – check your model’s user manual. 

How to change lawn mower oil

(Image credit: Getty)

When you need to seek help with your gas lawn mower

If you find pools or stains of oil below your machine when it has been standing for a while, it may have a leak. If your machine emits black smoke, it may be burning oil. In both cases, you should visit your machine’s manufacturer or retailer for help and advice. 

Sally J. Hall

Sally J. Hall is an editor and journalist who has written for many newspapers, magazines and websites on a wide range of subjects within the medical, parenting, and consumer product markets; she is also the author of three books.