How Overfilling Oil in Your Subaru Can Cause Major Engine Damage

As a Subaru car owner, it’s crucial to maintain your vehicle properly to ensure it runs smoothly and efficiently. One of the most important aspects of car maintenance is ensuring that the engine oil levels are correct. Overfilling the oil in your Subaru can have severe consequences that can lead to costly repairs and reduced performance. In this article, we will discuss what happens when you overfill oil in your Subaru and how to prevent and fix this problem.

Effects of Overfilling Oil

Your car’s engine relies on a steady flow of oil to lubricate its various components and keep them running smoothly. When you overfill the engine with oil, it leads to higher pressure inside, causing leaks and reduced performance. Here are some of the most severe effects of overfilling oil in your Subaru:

Engine Damage

The engine can suffer severe damage if overfilled with oil. The excess oil can compromise the engine’s moving parts, such as the piston rings, rod bearings, and crankshaft, leading to accelerated wear and tear. This can cause the engine to malfunction, overheat, and ultimately fail, requiring expensive repairs or replacement.

Reduced Performance

Overfilling oil can lead to reduced engine performance, decreased fuel efficiency, and increased emissions. The excess oil inside the engine can cause the oil pump to work harder than normal, leading to sluggish acceleration and poor fuel consumption.

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Overfilled oil can cause leaks in the engine seals and gaskets, leading to oil seepage and subsequent contamination of other engine components. The seals and gaskets are designed to work optimally within a certain range of oil levels, so overfilling oil can compromise their effectiveness.

How to Prevent Overfilling Oil

Preventing overfilling oil is easy but requires attention to detail. Here are some simple steps you can take to ensure you don’t overfill oil in your Subaru:

  1. First, determine how much oil your Subaru engine needs. This information can be found in the owner’s manual or by checking the oil capacity label under the hood.

  2. Check the oil level regularly using the dipstick or oil level gauge when the engine is cold. Insert the dipstick into the engine, wipe it off and re-insert it back into the engine, making sure it sits firmly. Check the oil level against the markers on the dipstick.

  3. Be careful not to add oil in excess when topping up oil levels between oil changes.

  4. Always wait a few minutes to allow the oil to settle before taking a final reading.

How to Fix Overfilling Oil

If you have already overfilled oil in your Subaru, the best solution is to remove the excess oil immediately. Here’s how to do it:

  1. Find the oil drain plug and remove it carefully using a wrench.

  2. Drain the excess oil from the engine into a clean container.

  3. Replace the oil drain plug.

  4. Refill the engine with the proper amount of oil, ensuring you don’t exceed the recommended levels.

  5. Start the engine and allow it to run for a few minutes to allow the oil to circulate within the engine.

  6. Check the oil level using the dipstick and ensure it’s within the recommended range.

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Frequently Asked Questions (FAQ)

Can overfilling oil lead to a blown engine in my Subaru?

Yes, overfilling oil can lead to blown engines, especially if left unaddressed for an extended period. The excess oil can cause increased engine pressure, leading to failed gaskets, seals, or other components, ultimately resulting in engine failure.

Can I drive my Subaru if it has overfilled oil?

It’s not recommended to drive your Subaru with overfilled oil as it can cause damage to the engine. If your engine has too much oil, drain the excess oil immediately and ensure the engine oil level is correct before driving your car.

How often should I check my Subaru’s oil levels?

It’s recommended to check your Subaru’s oil levels regularly, especially before long trips or every few weeks. You can use the dipstick, oil level gauge, or digital oil monitoring system in newer models to check the oil levels. It’s also essential to change your car’s oil regularly, as recommended by the manufacturer.


Overfilling oil in your Subaru can have severe consequences that can lead to engine damage, reduced performance, and leaks. To prevent overfilling, regularly check the oil levels and ensure you add the proper amount of oil. If you have already overfilled your engine, drain the excess oil immediately and refill with the correct amount. By following these simple steps, you can avoid costly repairs and ensure your Subaru runs smoothly and efficiently for years to come.

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Joseph Weaver

With a background in engineering and a passion for cars, Joseph brings a unique perspective to our blog. He's particularly interested in the technology and innovation behind Subaru's advanced safety features, and his articles on this topic are always insightful and informative. When he's not writing, he enjoys playing video games and spending time with his family.

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