Learning how to change oil in riding lawn mower is a fundamental skill for any homeowner. Changing the oil in a riding lawn mower typically involves accessing the drain plug from underneath the machine. This routine maintenance is crucial for keeping your mower’s engine running smoothly and extending its lifespan for many seasons.
You can save time and money by doing it yourself. This guide provides clear, step-by-step instructions to make the process straightforward, even for beginners.
We will cover everything from gathering the right supplies to the final check. Let’s get started.
How To Change Oil In Riding Lawn Mower
This section provides the complete, detailed procedure. Always refer to your owner’s manual first, as some models may have specific requirements or alternative drain methods. Your manual will also specify the exact type and amount of oil needed.
Gather Your Tools And Materials
Before you begin, collect all necessary items. Having everything on hand will make the job quicker and cleaner. You will need:
- Fresh engine oil (check manual for correct viscosity, e.g., SAE 30 or 10W-30)
- A new oil filter (if your mower has one)
- An oil drain pan or suitable container
- A socket wrench or adjustable wrench for the drain plug
- An oil filter wrench (if applicable)
- Funnel
- Clean rags or paper towels
- Latex gloves to keep your hands clean
- A piece of cardboard or a tarp to lay on
Prepare Your Riding Lawn Mower
Proper preparation ensures a safe and effective oil change. Follow these steps before draining the old oil.
Run The Engine To Warm The Oil
Start the mower and let it run for 5-10 minutes. Warm oil flows out more easily, carrying more contaminants with it. Be careful, as the engine and oil will be hot. Park the mower on a flat, level surface for this step and the entire process.
Park Safely And Engage The Parking Brake
Turn off the engine and remove the ignition key. Engage the parking brake fully. If your model has a brake pedal lock, use it. This prevents the mower from rolling while you work underneath it.
Disconnect The Spark Plug Wire
Locate the spark plug and disconnect its wire. This is a critical safety step that prevents the engine from accidentally starting while you are working on it. Secure the wire away from the spark plug terminal.
Drain The Old Engine Oil
Now you are ready to remove the old, dirty oil. There are two primary methods: using the drain plug or using a siphon pump through the dipstick tube.
Locate And Remove The Drain Plug
Carefully slide your drain pan under the mower’s engine. You may need to raise the front of the mower slightly for better access; use ramps if you have them. Never crawl under a mower supported only by a jack. Find the drain plug on the bottom of the engine oil pan. It is usually a bolt or hex-head plug.
Place your drain pan directly under the plug. Using your wrench, slowly turn the drain plug counterclockwise. Once loose, unscrew it by hand but be prepared for hot oil to flow out quickly. Let the oil drain completely into the pan. This may take several minutes.
Alternative Method: Siphon Pump
Some mowers are difficult to access from underneath. For these, an oil extractor or siphon pump is a handy tool. Insert the pump’s tube down the dipstick tube until it reaches the bottom of the crankcase. Pump the oil out into your drain pan. This method can be cleaner but may not remove all sediment from the bottom of the pan.
Replace The Oil Filter (If Equipped)
Many riding mowers have a spin-on oil filter. Changing it with every oil change is recommended for optimal engine protection.
Place your drain pan under the filter to catch drips. Use an oil filter wrench to turn the old filter counterclockwise until it loosens. Remove it by hand. Before installing the new filter, dab a little fresh oil on your finger and wipe it around the rubber gasket on the top of the new filter. This ensures a good seal.
Screw the new filter on by hand until the gasket makes contact, then tighten it an additional three-quarter turn. Do not overtighten it with the wrench.
Reinstall The Drain Plug And Add New Oil
Once all the old oil has drained, wipe the drain plug and the hole clean. Check the drain plug washer for wear and replace it if necessary. Screw the drain plug back in by hand, then tighten it securely with the wrench. Avoid overtightening, which can strip the threads.
Locate the oil fill cap on top of the engine. Place your funnel in the fill hole. Slowly pour in the recommended type and amount of fresh oil. Check your manual for the exact capacity; it’s often between 48 and 64 ounces. Stop periodically to check the dipstick, ensuring you do not overfill.
Check The Oil Level And Clean Up
After adding most of the oil, wait a minute for it to settle in the crankcase. Remove the dipstick, wipe it clean, reinsert it fully, and then pull it out again to check the level. The oil should be between the “Full” and “Add” marks. Add small amounts of oil if needed to reach the correct level.
Once the level is correct, replace the oil fill cap securely. Reconnect the spark plug wire. Properly dispose of the old oil and filter at an auto parts store or recycling center that accepts used oil. Never pour it on the ground or into a drain.
Start The Engine And Perform A Final Check
Start the mower and let it run for a minute. This circulates the new oil and allows you to check for leaks around the drain plug and filter. Turn off the engine, wait another minute, and recheck the dipstick level one final time. Top up if necessary.
Congratulations, you have successfully completed an essential maintenance task. Your mower’s engine is now protected for another season of reliable operation.
Choosing The Right Oil And Filter
Using the correct oil and filter is as important as the change itself. Using the wrong type can lead to poor performance or engine damage.
Understanding Oil Viscosity And Types
Oil viscosity refers to its thickness. Common types for mowers include SAE 30 for warmer climates and 10W-30 for areas with wider temperature swings. Always use oil classified for “small engines” or at minimum, an API-rated automotive oil. Synthetic blends or full synthetics offer superior protection and can extend intervals between changes.
Finding The Correct Oil Filter
Oil filters are not universal. The model number is usually printed on the side of the old filter. If not, take your mower’s make, model, and engine serial number to a dealership or parts store. They can cross-reference the correct part for you.
Common Mistakes To Avoid
Awareness of common errors can help you avoid costly problems.
Overfilling Or Underfilling The Oil
Too much oil can cause excessive pressure and lead to seal leaks or engine damage. Too little oil results in inadequate lubrication and rapid engine wear. Always use the dipstick to get the level just right.
Forgetting To Replace The Drain Plug Washer
A worn or cracked washer on the drain plug can cause a slow leak. It’s a cheap part, so replace it if there’s any doubt about its condition. This ensures a tight, leak-free seal.
Using Incorrect Tools Or Overtightening
Using the wrong size wrench can strip the drain plug. Overtightening the drain plug or oil filter can damage threads or crush gaskets, leading to leaks. Tighten firmly but with care.
Frequently Asked Questions
How Often Should I Change My Riding Mower Oil?
Most manufacturers recommend changing the oil every 50 hours of operation or at least once per mowing season. If you use your mower heavily, consider changing it more frequently. Always check your owner’s manual for the specific interval for your model.
What Is The Best Way To Change Oil In A Lawn Mower Without A Drain Plug?
For mowers without a traditional drain plug, the siphon pump method through the dipstick tube is the standard approach. Some models may have a special drain valve or tube you can attach a hose to. Again, your owner’s manual is the best resource.
Can I Use Car Oil In My Riding Lawn Mower?
You can generally use a high-quality automotive oil if it matches the recommended viscosity. However, oils formulated specifically for small engines often have additives better suited for the higher operating temperatures and different stress patterns of lawn mower engines. For optimal performance, choose small-engine oil.
How Do I Dispose Of Old Lawn Mower Oil?
Used motor oil is a hazardous waste. Most auto parts stores and service stations accept it for recycling at no charge. Store the used oil in a clean, sealed container like the jug from the new oil. Take the used oil filter in a plastic bag as well, as many locations accept those too.
Is It Necessary To Change The Oil Filter Every Time?
Yes, it is highly recommended. The filter traps harmful contaminants. A new filter ensures your fresh oil stays clean and provides the best protection for your engine’s internal components. It’s a small cost for significant added protection.