What Kind Of Fluid Goes In A Zero Turn? (What You Need to Know)

When it comes to lawn care, there are a lot of different machines that you can use to get the job done. One of the most popular machines for homeowners is the zero turn mower. These mowers are known for their maneuverability and speed, making them perfect for large yards. But what kind of fluid goes in a zero turn? 

What Kind of Oil Goes in a Zero-Turn Mower? 

Zero turn lawnmowers will use a 20W-50 or 15W-50 synthetic motor oil. When trying to pinpoint the right oil for your mower, the first step should always be to check the manufacturer’s recommendations in your user manual. 

That will save you time; it’ll also ensure that you get the best-suited oil for your machine. If your manual isn’t available, the following paragraphs should help you make a selection.

Is Motor Oil a Good Choice?

Motor oil is one of the most common machine oils out there. It’s composed of base oils mixed with additives like dispersants and detergents

It’s used to lubricate the engine inside machines and keep the engine clean from sludge. It’s also used to deal with harmful acids that come from fuel.

Your first thought might be to use motor oil for your mower since it’s the more accessible, popular choice. And while it might do the job, it isn’t considered the best choice for your mower long-term. 

Motor oil will generally work with your mower, and it’ll do its job without an issue. However, the problem lies within the formula of motor oil. Because motor oil isn’t formulated for the usage of hydrostatic mowers, it might pose an issue for your mower’s internal parts. 

As we stated before, motor oil contains certain detergents and chemicals. These substances won’t necessarily affect your unit’s performance in the short term, but they’ll cause precipitation inside your mower’s parts. 

The accumulation of these precipitated substances can lead to oil foaming and compromise the mower’s performance.

Which Kind of Oil Is Right, Then?

Now that you know that motor oil isn’t the best choice available, you’re probably wondering, which kind of oil is the right one?

Most manufacturers advise users to use transmission oils for zero-turn mowers, including hydro-gear wheel motors.

Unlike motor oil, transmission oil keeps your machine’s parts lubricated without any risk of substance precipitation. 

Not only that, but it also assists the internal parts in functioning smoothly by providing hydraulic pressure. It also helps make turns in steering more smooth without taking a toll on the parts. 

One of the best choices of transmission oil is 20W-50 oil and 15W-50 oil.

20W-50 Oil

20W-50 transmission oil has numerous advantages, with the most notable one being that it’s budget-friendly. And as mentioned before, it’s guaranteed not to harm your mower’s parts with any residual substance.

It helps with oxidation, shock differences, and keeping your mower’s temperature at a normal level as well.

15W-50 Oil

15W-50 transmission oil can also be a good fit for you as It has the same functions as the 20W-50 oil. 

What differentiates 15W-50 oil from 20W-50 oil is that the 15W-50 can operate in freezing temperatures. 

It also provides high resistance to thermal damage to your mower’s parts and engine and overall protection of the internal gear’s durability. So if you live in a cold country, or if winter where you live, is quite frigid, the 15W-50 is the pick for you.

When and How to Change Your Zero Turn’s Oil

Let’s take a look into how to change your zero-turn mower’s oil and when is the right time to change it.

When to Change the Oil

Generally speaking, you should check your mower’s oil every time you use it. Your mower might be affected by certain conditions such as rough terrain, wet grass, and high temperature, which will cause a need for oil change often. 

That said, it would be best if you check regularly. You’ll be able to tell if your machine needs an oil change through the oil’s color. 

During the application of oil, you’ll notice that the oil is a bright golden color. If you find the oil to be a dark brown color, it’s become dirty and no longer capable of protecting your mower’s parts.

Your mower’s oil should be changed in two cases: either after every mowing season or after every 50 hours of operation. And if your mower is brand new, you’ll have to change the oil after the first five hours of use.

Now that we know the right time to change the oil let’s dig into how to change it.

How to Change the Oil

Before starting the process, don’t forget to check your mower’s manual to know the best oil choice for your mower model. 

Here are the steps you need to follow to change your mower’s oil:

  1. First, grab a dipstick and check the oil level. If the oil level is between two holes on your dipstick, you can proceed. This is a crucial step because it’s vital not to overfill your engine, or it’ll backfire with the results. As the saying goes, too much of a good thing is bad.
  2. Next, it’s time to drain the old oil inside your zero-turn. You’re not limited to using just the dipstick to do that; you can also use an oil extractor or a draining tube as well.
  3. The next step would be to leave your mower open for about 15 minutes. That is because if the oil is warm before removing it, it will drag with it any dirt and precipitation on the engine.
  4. After 15 minutes, turn off your mower and disconnect its plug. Then, place a plastic bag over the gas tank and shut the cap well to avoid gas leaks.
  5. After finishing all the previous steps, the oil is ready to be extracted. Insert your extraction tool of choice and drain the oil out of the engine into a container.
  6. After draining the old oil, save it aside in its container for later. You’ll be able to recycle it at the nearest dealership available.
  7. Lastly, start adding the new, clean oil, and after you’re done, don’t forget to check the oil level and make sure it’s correct. 

And with that, your zero-turn mower is ready to go!


It’s no secret that zero-turn mowers are becoming everyone’s favorite pick today. But, of course, it’s due to their small size and easy navigation.

Keeping your zero-turn in tip-top condition will guarantee you a neat, well-tamed lawn for many years to come. That said, it’s essential to know precisely the kind of fluid that goes in a zero-turn, when to change it, and how to change it. 

Don’t opt for motor oils. Instead, opt for transmission oils. Stay consistent with your oil checks to make sure the oil inside your mower isn’t old or dirty. Most importantly, if it’s available to you, don’t forget to check your user manual or the company website for your brand and model number.

Happy mowing!

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