Mower Oil vs. Motor Oil: A Guide to the Right Lawn Mower Engine Oil

The answer to the question is yes, you can use motor oil for a mower, but only if it has a four-stroke engine.

Four-stroke engines use oil to lubricate and move the internal parts, and they are smoke less when compared to their two-stroke counterparts.

blue plastic mower oil bottle

One of the main considerations when thinking of oil for your mower is viscosity.

SAE 30 is ideal for warmer temperatures while SAE 10W-30 is recommended for cold weather. SAE stands for Society of Automotive Engineers, and the W in 10W-30 means ‘winter.’

Viscosity is generally the thickness of oil at specific temperatures because texture will be affected by temperature. The thicker the oil, the higher its viscosity and the slower it will be consumed.

Each oil you find on display will have a label for viscosity. Your manual will stipulate the oil you should use, and so you want to ensure you have gone through it conclusively.

If your mower runs on a two-stroke engine, then you will need to mix oil and gasoline to get the optimal combo to run the internal parts of your engine.

Regular motor oil has detergents and additives that could harm your two-stroke engine, which is why you should avoid it.

The API – American Petroleum Institute – rates and classifies oils, and so two-stroke engines require those oils with these labels; SF, SG, SH, and SJ.

These codes signify that the oil has no additive that could harm your mower’s engine. If you go through the manufacturer’s manual, you won’t have to worry about the type of oil to use for your engine.

Mono Grade Oil (SAE 30) and Multi-grade Oils (SAE 5W-30)

Because temperatures matter, a mono-grade oil – SAE 30 – is tested on engines that operate at temperatures not exceeding 210°F.

grey SAE 30 mower oil

For small engines used in temperatures ranging from 40°F to 100°F, manufacturers recommend the use of SAE 30.

Also worth noting, the same viscosity is recommended for both gas-powered and automotive engines.

For multi-grade oils, SAE 5W-30 is recommended, and it is tested on engines running at 210°F. As the W suggests, this rating is for mowers used in relatively cold areas.

The reason why SAE 5W-30 is used in mowers that operate in cold areas is because the oil is scooped and splashed ideally, lubricating internal parts so the engine can operate the same way – and with the same viscosity – as a SAE 30 in 210°F.

Multi-grade oils have internationally recognized codes; GF-3, GF-4, and GF-5. ILSAC GF-5 to signify quality.

When to Change Mower Oil

For your mower to work perfectly every time, you want to drain old gasoline after each session.

Oil does not need regular changing, but only when it turns a dark black, or when you notice too many floating debris this means you have to check it regularly to be sure the level and content are good at all times.

Your manual will include vital information, such as the required level of oil, and so you will want to top it up once it hits levels below that.

Additionally spring is the best time for an oil change, as it is mostly the beginning of regular mowing season.

changing mower oil

If your oil looks good and you aren’t sure when to change it, then once a year is fine, but also dependent on the frequency of mower use.

When your engine is still new, or you are using it for the first time, oil change is necessary after the first 5 hours of use. Also, rough terrain, wet grounds, and dusty lawns will necessitate regular change of engine oil.

The more you get in the habit of checking your oil unit, the more you will be informed of the state of your mower’s oil.

Changing Engine Oil

You will need to prep your engine first by warming it up, and then cleaning the fill area.You want to place a pan underneath to catch any oil that escapes to reduce the amount of cleaning up later.

Once you have drained the oil using a drain plug, you can go ahead and change the oil. If your mower has an oil filter, you want to change it at this point.

Your manual will include details on the right amount of oil to use as you don’t want to under-fill or overfill your tank.

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