What Happens If You Overfill Engine Oil?

If you own a vehicle, you may have encountered the frustration of overfilling your engine oil.

It’s a frequent error that anybody may make, but it’s critical to correct the problem right away to minimize engine damage.

In this article, we’ll look at what happens when you overfill your vehicle’s engine oil and how to rectify the problem.

Whether you’re a seasoned mechanic or a novice, you’ll discover useful suggestions and information to help you address this problem and keep your vehicle running smoothly.

An image of a technician removing excess engine oil after overfilling
Draining excess engine oil Source: dubizzle

What Quantity of Oil is Necessary for a Car?

The required oil volume for a vehicle can vary. Therefore, before adding or changing oil, it’s essential to know your car’s oil capacity.

For specific amounts, it’s advisable to check your car’s manufacturer’s manual for the exact amount and recommended oil type.

However, most engines typically require between 4 to 6 quarts of oil.

Also note that, the amount of oil required increases with engine size. For instance; 

  • Three-cylinder engines: 3 litres of oil
  • Four-cylinder engines: Approximately 4.5 liters of oil
  • Six-cylinder engines: 5.5 litres of oil
  • Eight-cylinder engines: Between 4.5 and 7.5 litres of oil

What Happens If You Overfill Engine Oil?

Excessive engine oil can lead to frothing and the formation of air bubbles, which prevents proper lubrication of engine parts.

Consequently, this may result in increased wear and tear, diminished power, and reduced efficiency.

In severe cases, too much oil can cause engine breakdowns or expensive repairs.

Here are some additional issues that may arise:

Engine Damage – Overfilling can cause critical engine damage. The surplus oil may disrupt the crankshaft’s movement, leading to contact with the oil, increased friction, heat, and the risk of engine failure.

Aeration and Foaming – Too much oil can lead to the crankshaft stirring the oil into foam. This may result in aeration and foaming. which compromises the oil’s lubrication and cooling functions for the engine parts.

Increased Oil Pressure – An overfilled engine can have increased oil pressure, which might harm oil seals and gaskets, resulting in leaks.

Oil Leaks – overfilled oil levels can push extra oil through the piston rings to the combustion chamber, leading to oil combustion, spark plug contamination, and higher emissions. Additionally, oil might also seep from seals and gaskets, creating a mess and possibly harming other engine parts.

Reduced Engine Performance – Overfilling oil can increase resistance in the moving parts, causing a decline in engine performance and fuel economy.

Damage to Seals and Gaskets – Too much oil can exert undue pressure on engine seals and gaskets, resulting in leaks and potential engine harm.

Catalytic Converter Damage – Burning too much oil in the combustion chamber can pollute the catalytic converter, diminishing its efficiency and possibly causing damage.

Symptoms of Overfilled Engine Oil

If your engine oil level is too high, you might notice certain indicators. Below are five typical signs:

  • Check Engine Light

Overfilling engine oil may lead to increased oil pressure, which can activate the check engine light.

  • White or Blue Smoke

If there’s too much oil, it can burn within the engine, resulting in white or blue smoke from the exhaust.

  • Oil Leaks

When there’s too much oil, it can exert extra pressure on the engine’s seals and gaskets. This can potentially cause them to break and leak oil.

  • Diminished Engine Efficiency

The high pressure and reduced lubrication from too much oil can cause poor engine performance.

This could manifest as reduced power and acceleration.

  • Abnormal Engine Sounds

Overfilling oil may lead to the formation of air pockets within the oil, leading to foaming.

This reduces its ability to lubricate, which can produce unusual engine sounds such as knocking, tapping, or ticking.

Correcting an Engine after Overfilling with Oil

To rectify an engine that’s been overfilled with oil, it’s critical to act quickly to avoid damage to the engine.

Follow these steps to correct the issue:

Verify Oil Level with Dipstick – Use the dipstick to gauge the oil level and ascertain the excess amount to be removed.

Eliminate Excess Oil – Use an oil extractor or take out the drain plug to release the extra oil. Ensure you gather the oil and dispose of it responsibly.

Substitute the Oil Filter – Should the oil filter be compromised or malfunction due to the overfill, replacing it is necessary.

To ensure your engine oil is at the appropriate level after correcting an overfill:

Reassess Oil Level/Check Oil Level – Use a dipstick to check the oil level to ensure it’s within the minimum and maximum indicators.

Start Engine – After verifying the correct oil level, start the engine to observe any leaks or listen for any irregular sounds.

Remember, if you’re unsure about conducting these procedures on your own, it’s wise to consult a professional mechanic.

They can guarantee that the engine is correctly serviced and operational.


So, what happens if you overfill your car’s engine oil? Overfilling your engine oil may result in several issues of varying severity.

This may impact your car’s performance and durability.

Should you come across any of the signs or issues mentioned, it’s important to address them swiftly.

The quicker you resolve these issues, the less risk there is to your engine.

Sticking to the provided instructions can also help prevent engine damage.

If you’re unsure about handling the issue yourself, don’t hesitate to consult a professional mechanic.

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