Can You Use Car Oil in a Lawn Mower?

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The oil that you put into your lawnmower can have a huge positively or negatively impact on it. It is imperative that you put the right type of oil in your lawnmower if you want it to function properly and you must make sure that you perform the basic maintenance task of changing the oil regularly.

Performing the task of draining and changing the oil in your lawnmower is an essential task due to the fact that oil carries away the ash and carbon that is brought about by combustion in the high-temperature whirlwind of the lawnmower’s small engine.

However not all oils can be used in the different types of engines that some lawnmowers have. The quickest and easiest way to find out what the best type of oil is to put in your lawnmower is to check the owner’s manual.

A lawnmower can either have a two-stroke engine or a four-stroke engine; it is important to know what type of engine your lawnmower has before you decide the type of oil to use.

For years, the manufacturers of these lawnmowers normally offer a choice between the two-stroke and the four-stroke engine. But what we have noticed recently is that the four-stroke engine lawnmowers are now dominating sales.

Although the two-stroke, and four-stroke engine lawnmowers work exactly the same way, which is cutting through the grass with a blade that is spun at a very high speed by the engine. There are some major differences between these two types of engines and we are going to talk about them below.

Fuel Differences

The biggest difference that has been noticed by owners of the two-stroke and four-stroke engine lawnmower is the difference in fueling. The two-stroke engines require the user to mix oil with the gas; this is due to the fact that what lubricates the internal moving parts of the engine is the oil in the gas. On the other hand, what lubricates the internal moving parts of the four-stroke engine is the oil that is drawn from a reservoir located in the crankcase. The gasoline moves into the fuel tank and doesn’t mix with the oil.

Engine Differences

The difference between the two-stroke engine and the four-stroke engine here is that the piston found in the two-stroke engine has a power downstroke that occurs twice as much as the piston found in the four-stroke engine. This is what makes the two-stroke engine have twice as much power as the four-stroke engine. A two-stroke engine is smaller and lighter than a four-stroke engine that has the same power output; this makes two-stroke lawnmowers lighter than four-stroke lawnmowers.

Other Notable Differences

Some other differences between the two-stroke and four-stroke engine include:

  • The two-stroke engine is louder and produces more smoke than the four-stroke engine, which means that it causes more noise and air pollution.
  • The four-stroke engines tend to lose their oil flow if oil pools on one side of the reservoir when you try to mow steep slopes, while the two-stroke engine can work in any position.
  • It is easier to start up a four-stroke engine than a two-stroke engine, and it also stands up better under constant heavy usage.

Is Car Oil Suitable for Your Lawn Mower?

Once you know which type of engine your lawnmower is running on; you can move onto if car oil is suitable for your lawnmower:

Two-stroke Lawnmowers

Most owners of a two-stroke engine lawnmower know that it requires the gasoline to be mixed with oil. And the mixture with gasoline requires a lightweight oil so as to lubricate all the parts of the fast-moving and lightweight engine. So, two-stroke lawnmowers cannot use car oil. If you own a two-stroke lawnmower, it is advisable that you purchase the specific type of oil that the manufacturers of this type of lawnmowers sell. Some of the makers also specify alternative lightweight oil having designations like NMMA-TCW3.

Four-stroke Lawnmowers

The four-stroke lawnmowers are becoming more common, and they act like automobiles as they store gasoline and oil in different compartments. They can make use of car oil, but also make sure you check the owner’s manual because they can be sensitive to additives and alternatives. Some of the makers say it’s advisable to use a detergent additive or synthetic oil. Generally, these lawnmowers can use straight SAE 30 weight oil or even multi-viscosity oil such as SAE 10W-30 oil.

Check out some of the Best car oils for your four-stroke lawnmower.

When to Change the Oil of Your Lawn Mower

You can check the lawnmower’s owner’s manual to know the best intervals for changing the oil regularly. It is normally said that you should change the oil after about 25 hours of usage. But if you are the kind of owner that uses the lawnmower to mow an exceptionally dusty area, you should probably change it more often.

If for some reason you don’t have the owner’s manual, then make sure that you change the oil in the spring, before the start of another mowing season. Changing the oil before the start of every other mowing season should be the longest interval between the oil changes.

How to Change the Oil in Your Lawn Mower

Before you change the oil in your lawnmower, there are a few steps you might want to take, such as disconnecting the spark plug which will prevent the mower from starting by accident during the oil changing process. You might also want to removing the gasoline preventing it from spilling all over the place when you change the oil due to the fact that you will have to tilt the mower to one side. You should also let the mower run for a bit to warm it up which will warm up the oil making it more viscous (thinner or runnier) so that it will flow much easier and fully To find out how to remove the gas please read this section Safety First of our How to Dispose of a Gas Lawnmower article.

Very few lawnmowers have an oil drain plug which you can just open to easily drain the oil out. But if yours doesn’t have an oil drain plug, then you can just tilt it to one side and drain the oil whilst ensuring that the carburetor is on the raised side.


If you have a two-stroke lawnmower, then don’t use car oil. But if your lawnmower has a four-stroke engine, then it is safe to use car oil.