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Can You Use Car Oil in a Lawn Mower? (What You Need to Know)

Can You Use Car Oil in a Lawn Mower? (What You Need to Know)

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There’s no getting away from the fact that most of us still need oil to lubricate our lawn mowers. Even if you don’t like oil and want to move toward a more energy (and cost) efficient way of lubricating your mower, most of them still require oil and routine maintenance for it to continue to operate.

However, the very fact you need to pour oil into the engine time after time at each oil change might prompt car-savvy individuals to wonder if they could use car oil for the job.

If you happen to have a bunch of car oil sitting around, can you just “change the oil” before mowing your lawn?

Oil Quality

Oil Rigs

First and foremost, you don’t want to just pour any oil into your lawn mower, or any fuel tank for that matter. Poor oil quality is one of the quickest ways to cause problems for motors.

At best, poor oil can be inefficient slowly damage your engine. At worst, it might actually damage the engine or pose a real safety concern.

This is where the question of car oil comes in. To make a long story short, yes, you can use car oil to fuel your mower, but it needs to be of high quality.

For example, SAE 30 is one of the most commonly used types of high-quality motor oil on the market, and yes, it can be employed for both cars as well as lawn mowers. That said, there are several different types, including:

  • Standard SAE 30, which is good for smaller engines and use in warmer conditions
  • SAE 10W 30, which can work at a wider range of temperatures and is thus a better choice for colder weather, though it’s less efficient and is thus consumed more quickly than other SAE 30 oil options
  • SAE 5W-30, which is best for those looking for a more middle of the ground option
  • Vanguard 15W-50m which can be good for commercial use and thicker lawns

Finally, there is the question of synthetic oil. You may have already had this in mind when considering using “car oil” for your lawn mower oil. There are plenty of synthetic car oils on the market, so the question is whether they are compatible with your lawn mower.

That being said, you still need to make sure that this synthetic oil is on par with the SAE standard mentioned above.

This issue of compatibility also means that you won’t want to use something such as diesel or even ethanol-mixed fuel sources in your lawn mower’s motor.

Your mower’s engine is not designed to operate with these kinds of fuel sources, and that may be too much of a deviation from the more standard type of oil typified by SAE 30.

Accounting for Engine Size

Lawn Mower Engine Being Worked On

Size matters, and nowhere more so than in the world of engines and oil. Make the wrong match between the former and the latter and the consequences could be explosively awful.

One of the most important things to consider when pairing oil with lawn mower motors, therefore, is the size of the latter and the viscosity of the former.

This is another area where you might run into a catch when it comes to using car oil for your lawn mower, as not all oil designed with car motors in mind are compatible viscosity-wise.

As mentioned above, SAE 30 is the most common type of high-quality oil used with lawn mowers. You want to make sure that you are using the right type of SAE 30, such as 10W-30 or 10W-14, both of which are good fits for the size and type of motors that are typically included in lawn mowers.

When Should You Change Your Car/Mower Oil?

Synthetic Motor Oil

Before you start pouring any type of motor oil into your lawn mower, you might well wonder when you need to do so in the first place. After all, oil is costly, and the faster you use it up, the more costly it can be to keep your lawn mower continuously fueled.

If you can save oil, it’s almost always a good idea to do so. As such, you’ll want to wait and watch for signs that can indicate when it’s time to change your oil.

Many tanks often take about 20 ounces, but you’ll want to check yours before using it. What’s more, your owner’s manual should provide you with instructions as to how often you should expect to have to refill your tank.

You obviously do not want to lag behind this suggested timetable lest your lawn mower run out of fuel on you. At the same time, you don’t need to exceed it, lest you waste oil unnecessarily.

An average rate of usage is about 25 hours of usage, though this naturally depends on the kind of work you are doing. Heavy duty mowing work can require you to fill up the tank faster than if you went ahead with a more routine job in less intense circumstances.

What’s more, dusty environments can also cause you to have to refuel more frequently, or else turn to fuel sources that are more efficient in such environments, such as car fuel that works well in high heat and dust levels.

How to Change Your Oil

Pouring Motor Oil Into Engine

Once you have determined that, yes, it is indeed time to replace your lawn mower’s oil and you think that you have the right oil for the job, it’s time to get to it.

First of all, if you have a more modern model, your lawn mower probably has an oil drain plug. Look to see if you have this, because if so, this should make your task easier.

First, you need to make sure that the fuel tank is completely empty. This is not only necessary to make sure you are accurate when you pour more fuel into the tank so you are accurate with your measurements. As mentioned above, you don’t want to overfill the tank.

In addition, pouring out any remaining oil before refilling the tank can help ensure that the different types of oil don’t mix, which can be problematic if their consistency is radically different.

The Importance of Brand Name Recognition

Picking An Oil Brand

You may be able to use car oil in your lawn mower, but it needs to be oil that is recognizable and trustworthy. It is advisable to avoid generic oils, which might have all manner of additives without you knowing it, which can in turn cause problems for your mower’s motor.

Brand name recognition is also essential for making sure that the oil is on par with SAE 30 oil.

In addition, many lawn mowers recommend a certain kind of oil, so you want to match this as closely as possible. Try to either use the brand they provide or else something with a consistency which closely matches their type.

Some websites also include drop down menus that can give you oil recommendations based on the model of the lawn mower and motor you are using, which can make it all the easier to make sure you’re choosing the right oil, be it a car oil or made-for-mower oil.

Quality and viscosity are among the most important conditions to consider here, but if they are satisfied by the car oil you have on hand, there’s a fair chance you might be able to use it to power your lawn mower.


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