What Type of Lawn Mower Oil Should I Use?

Do you need to know what type of oil a lawn mower uses? Most gas-powered lawn mowers operate with 4-cycle engines. All gas-powered engines need sufficient oil to run smoothly and use the same oil to run as cars. There are many brands of oil to choose from, but your first consideration is the type of oil that works best for your mower.

Continue reading to determine what kind of oil you need, whether synthetic oil is safe, and how temperature affects your lawn mower's performance.

Best Lawn Mower Oil Types

Consider the temperature when choosing the best oil. These are the best oils to choose for your climate:

• SAE 30: Warmer temperatures, most common oil for small engines
• SAE 10W-30: Varying temperature range, this grade of oil improves cold-weather starting but may increase oil consumption
• Synthetic SAE 5W-30: Best protection at all temperatures, improved starting with less oil consumption
• SAE 5W-30: Very cold temperatures
• Vanguard 15W-50: Varying temperature range for continuous use, such as commercial lawn cutting or pressure washing

Lawn Mower Oil Capacity

Lawn mower oil tanks vary in size based on the type of lawn mower. Lawn mowers that get a lot of use should have their oil level checked more frequently. The start of the mowing season is an excellent time to check the oil level and top off if necessary.

Walk-behind mowers:

• Oil tank capacity: Typically 13 to 22 ounces
• Change oil: After 50 hours of use
  

Riding mowers:

• Oil tank capacity: Typically 48 to 64 ounces
• Change oil: After every 100 hours or annually

How to Check Lawn Mower Oil Level

Checking the oil level in your mower should be part of the preparations you make every time you mow. Neglecting to add oil when it's low can cause significant damage to your lawn mower.

Checking the oil level of a lawn mower is the same whether you have a ride-on or push-behind mower. The manufacturer's dipstick or indicator marks may differ slightly in design. Here's how to check:

1. Place mower on a flat surface: Ensure the lawn mower is on a level surface.
2. Remove dipstick: Remove the oil cap. The dipstick will be attached. Wipe off the dipstick indicator with a clean towel or rag.
3. Put the dipstick back: Replace the oil cap, tightening it.
4. Remove the dipstick again: Remove the oil cap again and read the top of the oil line against the dipstick's indicator marks.
5. Read the level: Indicator marks may vary. Some manufacturers use small holes (the top is the "full" mark, and the bottom is the "add more" mark). Other manufacturers use hash lines and might have "full" and "add" on the dipstick.
6. Add more oil, if necessary: If the oil level is low, slowly add more in small increments, about a few ounces. Recheck the oil level after adding each increment.
7. Do not overfill: Do not exceed or add more than the "full" level mark.
   

Choosing Lawn Mower Oil By Engine Type

Adding oil to a 4-cycle engine is an entirely different process than a 2-cycle engine. Lawn mowers with 4-cycle engines have two tanks—one for gas and one for oil, each added separately. 30-weight oil, used in many automobiles, is the most common weight used in lawn mowers. Weight refers to the viscosity or thickness. There are three types of lawn mower oil:

• Conventional
• Synthetic blend
• Fully synthetic

The best oil to use depends on the type of equipment you're using, the engine, and the temperature outside.

A few 2-cycle lawn mowers are still on the market, and this type of engine also runs other gas-powered yard equipment, such as weed-eaters and hedge trimmers. A 2-cycle mower has one tank with a combination of gas and oil, usually premixed by the homeowner. Information in your owner's manual will recommend which 2-cycle oil to use. They are generally lighter-weight synthetic blends, often labeled as performance or high-performance.

Lawn Mower Oil Types: Pros and Cons

Briggs and Stratton, a manufacturer of small engine equipment, recommends choosing a high-quality detergent oil classified as "For Service SF, SG, SH, SJ" or higher." Avoid using any special additives with these oils. The product label should also indicate whether the oil is synthetic or conventional.

The American Petroleum Association issues the classifications SF through SJ, which are used mostly for automobiles. The letters identify the best oils for automobiles manufactured during a specific period and cover a much more comprehensive range for lawn mowers.

Conventional Oil

Conventional oils are mineral-based products refined from crude oil pumped from a deep-underground oil well. Their most significant advantage is their cost, often about half the price of synthetic oils. However, synthetics are frequently less available or as accessible as conventional lawn mower oils.

Another reason to choose the conventional standard may be the age of your mower. While both types will work perfectly fine, your older engine may not be built for synthetic oil, which can cause lawn mower problems.

Full Synthetic Oils and Synthetic Blends

Synthetic oils are laboratory-created and developed using petrochemicals with a higher degree of refinement than crude oil.

Many of these types are blends that use conventional oil as a base. Further refinements are added to develop a more exact product for specific applications. These applications may include high-performance automobiles and high-use gas-powered equipment such as lawn mowers used in commercial landscaping.

The difference between fully synthetic and synthetic blends depends on the quality of the base oil used to create the product. The most pronounced difference between synthetic and conventional oil is the additives that make up synthetic oils. These include protection and better performance during temperature extremes, longer breakdown time for oil, and slower build-up of sludge and debris caused by impurities.

Some manufacturers claim that synthetic oils break down more slowly than conventional oils. However, regardless of the breakdown rate, you should change your lawn mower oil according to the timetable given in the owner's manual.

How to Change Lawn Mower Motor Oil

Walk-behind mowers need their motor oil changed every 50 hours of use, and ride-on mowers need their oil changed after 100 hours or at least once per season. It's best to change the oil when the tank is nearly empty and if the motor is warm after running.

The procedure is similar for walk-behind and ride-on mowers, but there is a slight difference in removing the oil. Here's how to do it:

1. Prepare the area: Lay down newspapers or a dropcloth to catch oil drips. Wipe clean the area around the oil tank.
2. Remove the old oil: For a push mower, remove the oil cap and tilt the mower over to drain the old oil. Collect it in an oil pan. For a ride-on mower, position the oil pan under the oil-drain sleeve or use a tube siphon or siphon pump to remove the old oil. Funnel all the collected oil into a plastic jug and seal it.
3. Add new oil: Push mowers have a 13-22 ounce capacity; ride mowers have a 48-64 ounce capacity. Refill the oil tank based on your mower's capacity. If unsure of your capacity, fill the tank to the lower end of the capacity for your type of mower.
4. Wait for oil to settle in the tank. Replace the cap and check the oil level according to the dipstick. Gradually add a few ounces and continuously check the level as you add more. Wait a couple of minutes to allow the oil to settle each time.
5. Get rid of the old oil: Old motor oil should be recycled. Consult Earth911.com for the nearest drop-off location.