Difference between Lawn mower oil and Car oil?

All machines that have moving parts need to be lubricated. Oil is one of the most common lubricants used today. There are varieties of oil for different applications depending on the type of machine.

While operating a lawn mower, I had a low oil situation. I was halfway through my mowing process and was out of lawnmower oil. I did have some car oil in the garage. I asked myself “Is car oil and lawn mower oil the same?” And what is the difference between lawn mower oil and car oil?

Car oils and lawn mower oils are similar, but not the same. Oils meant for lawn mowers have different additives than those found in car oils. Small engines are sensitive to these additives and they can damage the engine as well.

So read owner’s manual to find out which grade of oil is used for your lawnmower.

The answer surprised me, but I was curious to do more research. Read on as I share my knowledge with you about my discoveries in the process. I will also discuss other common queries regarding lawn mower oils. At the end of this article, I hope all your doubts regarding the same are cleared!

Lawn mowers have engines similar to that of automobiles, just that they are smaller and less powerful. They both have similar mechanisms for internal combustion. Due to their moving parts, both engines need lubricant for smooth and efficient functioning.

Lawn mowers however are operated in different circumstances. The engine and oil must be robust enough to withstand long periods of unuse, before being operated in dusty environments filled with dirt and debris. 

The primary requirement of lawn mower oil is that it should have good film strength and the ability to cling to dirt. These factors will allow your engine to run smoothly for long periods of time, allowing you to make the most out of your lawn mower.

Disclosure: Some of the links below may be affiliate links.

Can I use car oil in my lawn mower?

The answer depends on the type of engine on your lawn mower. four stroke engines use oils very similar to that of car oils. However, two stroke engines have lighter and faster moving components, which require a different type of oil. Thus, you cannot use car oil for these engines.

Four stroke engines are designed such that your gas and oil are stored separately. Larger versions of these types of engines are found in most automobiles as well. As a result, you can use car oil in your lawn mower if your engine is of this type. 

However, it is ideal to go through the manual of the lawnmower. This will outline the types of oil that your engine can handle. Some car oils also have additives that can damage the smaller engines over time. 

— Also read: When to Change Spark Plug on Lawn Mower?

Two stroke engines on the other hand are lightweight and small. They operate such that the gas and the oil are mixed before combustion. Most oils will also have to support the two-stroke motion of these engines. 

As a result, the oil needs to be light to lubricate the fast-moving internal parts. As a result, you cannot use car oil in these engines. Engine oils designed for two-stroke engines only have to be used for lawn mowers with this type of engine.

What will happen if I use car oil in a lawn mower?

If you use car oil in a two stroke lawn mower’s engine, you will cause serious damage to the engine and its internal components. If you use car oil in a four stroke lawn mower’s engine, your engine will run normally provided the type of oil is as specified in the manual.

But we still recommend you to read the owner’s manual first to find out the specific type of engine oil.

Having a four stroke engine will allow you to use most car oils that meet the engine specifications. This may not provide you the optimum performance, but you will still get the engine to work well without risking any damage.

This is not the case with two stroke engines. They require a different type of oil that is lighter. Using car oil will clog the engines. This will make the engine struggle to provide the required power to move forward, thus performing inefficiently.

Over the long run, there could be more serious implications with the engine getting damaged and failing completely.

The same is applicable to using improper engine oils with a four-stroke engine. While it may take longer for the damage to be irreparable, there will be evident signs that the oil used is not of the right type.

What happens if you don’t change oil in a lawn mower?

Over the long run, not changing the oil in a lawn mower can cause it to get dirty, which will clog the engines and damage it internally. As a result, the efficiency of the engine is reduced, and in some extreme cases, lead to engine failure over the long run.

However, machines with small engines like a lawn mower are designed for much shorter lifespans than automobiles. The average lifespan of a lawn mower is around 500 hours, beyond which there will be a host of problems that will force you to buy a new one.

By the time your engine oil degrades to the extent that it could cause engine failure, other problems on the lawn mower such as deck rust would have already forced you to change your mower. 

What oil goes in a four stroke engine?

The ideal oil for a four-stroke engine in warmer conditions is SAE 30. If you are going to operate the machine in an area with very cold winters, it is better to have the 10W30 engine oil instead.

One of the biggest factors that affect engine oil is temperature. As the weather gets colder, the viscosity of your engine oil drops considerably. This prevents the oil from freely moving around and coating the moving parts, thus diminishing its lubricating ability.

— Also read: Will Mowing Wet Grass Ruin a Lawn Mower?

Engines designed for warmer conditions do not have additives that help preserve the viscosity of the oil. SAE30 is one such standard oil used in both cars and lawnmowers. From here you can check some of the top SAE30 engine oils of Amazon.

The additives in oils designed for winter usage prevent the oil from thickening when there is a drop in temperature. This allows you to use the lawn mower in such conditions without worrying about a drop in performance. 10W30 oils are the most commonly used oils for four-stroke lawn mower engines.

How often should I change lawnmower oil?

It is ideal that you replace engine oil of your lawn mower every 30 hours or once before the regular mowing season resumes, whichever comes first. Or you can read the owner’s manual to find out the exact time, because this time can vary from model to model.

Engine oils designed for lawn mowers start to degrade around the 30-40 hour mark. This has a noticeable effect on the performance of the engine and can decrease its lifespan over the long run.

Many people find it hard to keep track of the exact number of hours they have used the mower for. In such cases, change your engine oil and oil filter while preparing your lawn mower for regular mowing during the summer or spring.

If you are using the mower for the first time, then change the engine oil after the first 5 hours of use itself. This helps you get rid of the tiny metal particles that may have mixed with the oil after the manufacturing process.

Related questions:

How do you know if my lawn mower needs oil? Use a dipstick to check the amount of oil in your engine. The dipstick will give you a clear indication if your engine has a low oil situation or you have filled too much oil.

How long can a lawn mower run without oil? If you do not have oil in the engine, it will get damaged as soon as you get it running. Within one or two minutes of running in this state, the engine will have suffered irreparable damage.

Will a lawn mower start with low oil? If your lawnmower has a low oil switch, then it will not start. If not, there is a higher chance of your engine seizing as soon you start it. If not, your engine could also start spin, but not start. This condition is more commonly known as letting go.