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Can Car Engine Oil Be Used in Lawn Mowers?


What if your lawn mower suddenly stops because it needs an oil change, but you only have your automobile oil? Or are you wondering why you should get different oils for your automobile and lawn mower, and you want an answer to the question, can car engine oil be used in lawn mowers?

Yes, you can use your car engine oil on your lawnmowers. Most lawn mowers manuals recommend 40 weight detergent oil, similar to the type of oil you use in your automobile engine. So, you do not have to go the extra mile to buy a different oil for your lawnmower, as long as it meets the manufacturer’s recommendation.

Types of Engine Oils

There are different types of engine oils available, and they are suitable for other machines—some of the standard engine oils.

male buyer chooses oil for car engine in store
  • SAE 10W 30: it is a relatively thick oil with the capacity to work at a wide range of temperatures. It is suitable for heavy-duty engines.
  • Standard SAE 30:  It is non-detergent motor oil, and its primary function is to trap and dissolve dirt in the engine. It is suitable for small engines and warm weather.
  • SAE 5W-30: It is a widely used motor oil because it is suitable for different engine types. It is helpful for lubrication, sealing, and protecting the engine’s components.
  • Vanguard 15W-50m: It is suitable for harsh working conditions and long hours of usage. They are primarily ideal for commercial use.

While considering these oils, bear in mind that there are synthetic car oils, and they might not be appropriate for your lawnmower. So ensure that the synthetic oil is the same as the SAE standard.

Two-Stroke vs. Four-stroke engine Oil

Two-stroke lawnmower engines were the typical type of lawnmower some years ago. But, in recent times, lawnmowers come with four-stroke engines.

Fourstroke engine oils can withstand dirt and protects the engine against wear and tear because it has a lot of zinc in its component. The oil has detergent additives to help get rid of dirt and debris. Also, the oil works well in extreme weather conditions due to its viscosity.

So a four-stroke engine oil is like an all-purpose oil; it cleanses the engine, lubricates it, cools it, and ensures the engine lasts longer.

If your lawnmower has a two-stroke engine, the oil you use can be synthetic, car engine oil, or oils. Twostroke engines do not have a separate tank for oil. Instead, you mix the oil with the fuel, which works fine.

The two-stroke engine oil reduces the friction and seals off the combustion gas to ensure it only passes through the combustion chamber.

Twostroke engines are more tolerant of different engine oils than four-stroke engines are. Know your lawnmower and act accordingly. 

How to Know Your Lawnmower Needs an Engine Oil Change

Before you decide to change your lawnmower’s engine oil, you must be sure it is due for a change. So that you do not waste your resources changing the oil when all it needs is more fuel. With how costly oil is, you should seek to save it when possible.

checking the oil in a lawn mower

Knowing when your lawnmower needs an engine oil change is similar to knowing when your car needs an oil change.  Use the same technique if you are familiar with changing your car oil.

First, you should know your tank size to know how often you should top up or change the oil. You can check your manual to understand how large the lawnmower’s fuel tank is.

The average 20 ounces tank size lasts up 25 hours of usage. So, considering how often and for how long you use it, you can know when to fill up the tank. This might vary if you do heavy-duty or intense work.

Also, if you are using the mowing machine in a dusty environment, you might have to refuel more often. In this situation, you should consider using a more efficient oil like the non-detergent motor oil (Standard SAE 30)

How to Refill Your Lawnmower Oil

You should get to it after deciding that it is the right time to change or refill your lawn mower’s oil and have a suitable oil for the engine.

Your lawnmower’s model determines the process of changing your oil. Newer models of lawnmowers and machine engines come with an oil drain plug. The oil drain plug makes your first step easier.

Step 1

First, you should drain your tank to get rid of the remnant oil and dirt in the tank to ensure the proper function of the engine. When different engine oil mixes, it can cause the lawnmower’s engine to knock. 

Also, draining the tank of remnant fuel makes it easier to fill the tank with accurate measurements. If you overfill the engine tank, the engine will not function well and will experience significant damage. Too much oil causes the engine to overheat and blow up or be hydro-locked.

If your engine has a spark plug, remove it and loosen the oil drain plug, and then the oil in the tank will completely drain off.

Step 2

After draining the oil and no drop of oil or dirt remaining in the engine, backtrack to tighten the plug again.

Step 3

Clean your engine filter to rid it of dirt. And if the engine filter needs a replacement, switch it for a new one.

Step 4

Pour the engine oil carefully to avoid exceeding the appropriate capacity level. And you are good to go. Cheek to see if there are leaks or spillage. Clean the engine and lawnmower and get to work.


In answer to your question ‘can car engine oil be used in a lawnmower?’, the answer as seen in this article is; that it depends on your lawnmower’s engine. Consult your manual before using any type of engine oil for your lawnmower.

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