Can You Put Car Oil in a Lawnmower? (Explained)

Can You Put Car Oil in a Lawnmower? (Explained)

If you own a lawnmower, you may have wondered whether it’s possible to use car oil in it. After all, both vehicles have engines, so it might seem logical to assume that the oil used in cars could also work in lawnmowers.

However, it’s important to understand the differences between the two types of engines and the specific oil requirements for each. In this article, we will explore whether it is safe and recommended to put car oil in a lawnmower.

Can You Use Car Oil in a Lawnmower?

The short answer is no, you should not use car oil in a lawnmower. While car oil and lawnmower oil may seem similar, there are key differences that make them incompatible. Lawnmowers typically use a four-stroke engine, while cars use a four-stroke or a two-stroke engine. These engines have different oil requirements due to their varying operating conditions and design.

Car oil is formulated to meet the needs of automotive engines, which operate at higher temperatures and have more complex lubrication requirements. It contains additives that help protect the engine from contaminants and reduce wear under high-stress conditions. On the other hand, lawnmower engines run at lower temperatures and have simpler lubrication needs. Using car oil in a lawnmower could lead to poor performance, increased engine wear, and potential damage.

Why Shouldn’t You Use Car Oil in a Lawnmower?

Using car oil in a lawnmower can have several negative consequences. Here are some reasons why it is not recommended:

  • Inadequate Lubrication: Car oil may not provide sufficient lubrication for a lawnmower engine. Lawnmower engines operate at lower temperatures compared to car engines, so they require an oil that can lubricate effectively in these conditions. Car oil may not flow properly or provide adequate protection against wear and tear in a lawnmower engine.
  • Increased Engine Wear: Lawnmowers have different internal components compared to cars, and using the wrong oil can lead to increased wear on these components. The additives in car oil that are designed to protect automotive engines may not be suitable for lawnmower engines. This can result in premature engine failure and costly repairs.
  • Potential Engine Damage: Using car oil in a lawnmower can cause damage to the engine over time. The oil may not be able to handle the lower operating temperatures of a lawnmower engine, leading to sludge buildup and decreased performance. It can also lead to overheating and damage to critical engine parts.
  • Warranty Void: If your lawnmower is under warranty, using car oil instead of the recommended oil can void the warranty. Manufacturers specify the type of oil that should be used in their lawnmowers for optimal performance and durability. Failing to follow these guidelines can result in the loss of warranty coverage.

What Oil Should You Use in a Lawnmower?

It is important to use the correct type of oil in your lawnmower to ensure optimal performance and longevity. Most lawnmowers require SAE 30 oil, which is specifically formulated for small engines. This oil is designed to provide adequate lubrication and protection for lawnmower engines operating at lower temperatures.

When choosing lawnmower oil, it is crucial to check the manufacturer’s recommendations. Some lawnmowers may require a different viscosity or a specific brand of oil. Consult the owner’s manual or contact the manufacturer for the correct oil specifications for your particular lawnmower model.

How to Change the Oil in a Lawnmower

Regular oil changes are essential for maintaining the performance and lifespan of your lawnmower. Here are the steps to change the oil in a lawnmower:

  1. Warm up the engine by running it for a few minutes.
  2. Turn off the engine and disconnect the spark plug wire to prevent accidental starting.
  3. Position a drain pan under the mower to catch the old oil.
  4. Locate the oil drain plug on the underside of the engine.
  5. Remove the oil drain plug and allow the old oil to drain completely.
  6. Once all the oil has drained, reinstall the oil drain plug.
  7. Fill the engine with the recommended oil through the oil fill tube. Be careful not to overfill.
  8. Check the oil level using the dipstick or sight glass, and add more oil if necessary.
  9. Reconnect the spark plug wire.
  10. Dispose of the old oil properly by taking it to a recycling center or an auto parts store.


In conclusion, it is not advisable to put car oil in a lawnmower. While the two types of engines may seem similar, they have different lubrication requirements. Using car oil in a lawnmower can lead to inadequate lubrication, increased engine wear, potential damage, and voiding of the warranty. It is important to use the correct oil recommended by the manufacturer for optimal performance and durability. Regular oil changes, following the manufacturer’s instructions, will help keep your lawnmower running smoothly for years to come.

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