The Top 3 Mistakes People Make When Changing Lawn Mower Oil

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Mowing is one of the best ways to transform your lackluster lawn into a stunning green oasis. But simply choosing the right lawn mower for your grass isn't enough. You must maintain the device, too. Case in point, you must change the oil at regular intervals, so that it works well and doesn't wear out quickly. Although it sounds simple in theory, people often make certain mistakes when changing their lawn mower's oil. To learn the most common errors as well as the right procedure for this routine maintenance task, House Digest sat down for an exclusive interview with Bryan Clayton, CEO of GreenPal. 

Sharing his experience, Clayton states, "I've changed the oil in probably over a thousand lawn mowers over the years, from when I was the mechanic in my landscaping company all the way up to now." According to Clayton, most common blunders people make when changing oil include not checking the oil levels, using low-quality lubricant, and failing to dispose of the old oil properly. These errors could damage your device and harm the environment at large.

Luckily, you don't have to worry too much because the oil doesn't need to be changed every few days. Although the high running temperatures, presence of water vapor, and introduction of debris deteriorates your lubricant's quality, it happens slowly over time. When prompted to share how often a mower requires oil changing, Clayton says, "Every 50 mowings is a good rule of thumb, or once a season if you're a homeowner. If you're cutting in dusty conditions or mowing more than once a week, go ahead and do it twice per season."

Opening up about the top mistake homeowners make when changing their lawn mower's oil, Clayton shares in his exclusive interview with House Digest that "People dump the new oil in and fire it up without checking the dipstick. Bad move." To avoid this mistake, you need to learn what the notches or stampings on the dipstick, a.k.a. the stick protruding out of your oil cap, mean. If your dipstick features hash marks (you'll see a crosshatched portion), the uppermost marking indicates a full engine, while the lowest point is an indicator of a low oil level. The 'F' (full) and 'L' (low)lines, 'Add' and 'Full' arrows, Max and Min stampings, or two holes piercing the stick all have the same meaning.

Ideally, you should add enough oil to your mower that it's between the two limits (it's okay if you add a little more) on your dipstick. However, don't go overboard, or your mower's engine might overheat. In the best-case scenario, it'll cause the rod or crankshaft to malfunction. But in extreme cases, the oil or the fuel might burst into flames. "You want to make darn sure you're in the right range before running it or you'll risk blowing the motor," adds Clayton. In case you add more lubricant than necessary, drain the excess out till you reach the full line.

Another mistake people make is not choosing a high-quality lubricant for their mower. In your quest to save money on the oil change, you may opt for lower-quality oil, and that's a mistake that can affect the lawn mower's performance in the long term. The device might overheat, suffer from carbon buildup, and experience motor troubles often. In other words, trying to save a few bucks upfront will cost you dearly down the line. Clayton agrees in his House Digest exclusive and says, "Yeah, [quality oil] costs a few bucks more, but it protects your engine better. [So], avoid cheap off-brand junk."

Check your owner's manual to find the right kind of lubricant for your lawn mower. In case you don't have one or can't find one, Clayton has a suggestion. "Most walk-behind mowers take 10W-30 or 10W-40 oil ... go with full synthetic if you want it to last," he says. "I personally recommend Mobil 1." 

Wondering what these numbers mean? They refer to an oil's viscosity (thickness), wherein the W stands for "winter." The lower the number preceding W, the higher the chances of the oil being stable when temperatures drop (this prevents overheating). Conversely, the higher the number after the W, the better the oil will perform when the engine heats up in the summer, since it keeps the internal metal components from rubbing against each other. Basically, use 10W-30 when you experience mild summers (temperatures don't rise above 77 degrees Fahrenheit) and use 10W-40 when you have to deal with mild winters only (temperatures don't drop below -13 degrees Fahrenheit).

Although it can be tempting to dump the old oil from your lawn mower down the drain or trash it with your regular garbage, this simple mistake has far-reaching consequences. For instance, if you pour it down your drain, the contaminated lubricant will harm your pipes and lead to blockages. Moreover, it'll pollute local waterways, harming plants, wildlife, and humans alike. According to the Environmental Protection Agency (EPA), used lubricant from a single oil changing session can taint nearly 1 million gallons of fresh water. 

And if you dump the old oil out in your yard, the birds visiting your garden will pay the price, since their feathers will stick to the toxic, heavy oil. This is why you should avoid sending the oil to a landfill. It'll take a long while to break down, during which time the constituent contaminants (including lead, chromium, arsenic, and cadmium) will continue harming the environment. Besides, there are laws and regulations for proper disposal of used oil in certain states, so check them out before disposal.

Clayton highlights the best way to get rid of old lawn mower oil in his House Digest exclusive. "Don't dump it in the trash or down a drain. I keep an old milk jug in the garage, fill it up with used oil, and take it to AutoZone or Advance Auto Parts... they will recycle it for free," he says. Just put it in a sealed container and avoid mixing it in with water, brake fluid, or antifreeze, as they'll contaminate it further and complicate the recycling process.

The first step is to wear safety goggles and don thick gloves. "Run the mower for a few minutes to warm it up," advises Clayton in his House Digest exclusive. About 15 minutes should do the trick. This step is important; according to Clayton, it "gets all the old gunk flowing so it drains out easier." Once the time is up, remove the spark plug to prevent the mower from starting while you're changing the oil. Place your device on a flat surface and seal its gas tank with a plastic zipper bag (place it between the opening and the cap) to keep it from leaking.

Now, it's time to locate the oil fill cap. You'll usually find it on the top or side. In case of confusion, refer to your owner's manual. "Tilt [the mower] on its side (air filter up) or use the drain plug if it has one." Place a large drain pan beneath (you can transfer it to a smaller container later) and drain the old oil into it. Wipe the dipstick on a clean microfiber cloth and set it aside. Give the mower a few minutes to drain completely, then put it back on its wheels. 

Next, "Replace the drain plug if needed, and fill [it] with about 2 quarts of full synthetic 10W-30 or 10W-40. Check the dipstick. Don't guess. Add more if needed — but don't overfill." Clean the stick after every dip to get a correct reading. Finally, replace the cap, wipe the mower clean, and you're done!

Besides avoiding the common mistakes listed above, you should follow a few best practices if you're changing your lawn mower's oil for the first time. The first tip on Clayton's list is to avoid multitasking. "Don't bother with sharpening your blades and changing the oil at the same time unless you've got the right tools. Do one job at a time and do it right," he emphasizes in his exclusive interview with House Digest. You don't want unwarranted accidents to negate your efforts.

The next tip is to gauge your comfort level and act accordingly. "If you're not comfortable tipping the mower to drain it, buy a little hand pump for 10 bucks. Makes life easier," Clayton says. We like Luigi's Siphon Pump. The one-time investment will make your oil changing sessions less of a chore. 

Regarding the best times to change oil, Clayton notes, "Do it in spring, and again in late summer if you're mowing a lot." Above all, have fun and put a little faith in yourself. The task might seem daunting, but it's as simple as replacing the pull cord on your lawn mower. "Changing your mower's oil yourself is one of the easiest things you can do to double the life of your engine. Just takes 15 minutes, a few bucks, and a little know-how," he concludes.