Top 9 Overfill Engine Oil Symptoms

Overfill Engine Oil Symptoms

Maintaining a car can feel like a never-ending list of tasks. From oil changes to tire rotations, it can be hard to keep track of what needs to be done and when. But one task that should never be overlooked is ensuring that your engine oil levels are at the correct amount.

Your engine oil is responsible for lubricating, cooling, and cleaning your engine, so it's important to make sure that it's at the right level to avoid any issues.

However, sometimes even the most careful car owners can accidentally overfill their engine oil. This simple mistake can seriously affect your car's performance, and knowing what to watch out for is important.

In this article, we'll go over the symptoms of overfilled engine oil and what you can do to prevent or fix them.

Whether you're a seasoned car owner or a new driver, understanding the signs of overfill engine oil symptoms can help you keep your car running smoothly and avoid costly repairs down the line.

What Happens When You Overfill Engine Oil?

Have you ever accidentally added too much engine oil during an oil change? It's a common mistake, but it can seriously affect your car's performance and longevity.

According to JD Power, overfilling your engine oil can lead to a range of problems that can cause significant damage to your engine if left unchecked. One of the most common issues caused by overfilling your engine oil is reduced lubrication.

When you add too much oil, it can become aerated or whipped into a foam-like consistency, reducing its effectiveness in lubricating your engine's parts. This can lead to increased wear and tear on your engine, as well as the potential for parts to seize up or fail entirely.

Overfilling your engine oil can also cause excess pressure to build up in your engine's seals and gaskets. This can cause them to fail, leading to oil leaks that can damage other parts of your engine or even create a fire hazard.

Also, if your engine oil is overfilled and burned in the combustion chamber, it can produce harmful byproducts that can damage your car's catalytic converter, causing it to fail emissions tests and potentially requiring expensive repairs.

Other symptoms of overfilled engine oil include decreased fuel efficiency, poor acceleration, loud driving sounds, engine overheating, and even engine failure.

In short, it's important to pay attention to the level of oil in your engine and make sure not to overfill it during routine maintenance. By doing so, you can avoid costly repairs and keep your car running smoothly for years to come.

Overfill Engine Oil Symptoms

Overfilling your engine oil can cause a range of issues that can negatively affect your car's performance and even cause damage to your engine. It's important to recognize overfill engine oil symptoms and take immediate action to correct the problem.

Here are some of the most common symptoms of overfilling engine oil, according to Car Services in Reading.

1. Odour of Burning Engine Oil

If you smell a disagreeable odor and notice a leak in the engine compartment, this could be a sign that engine oil has crept onto hot engine components and burned, creating an unpleasant smell.

2. Oil Puddle Beneath Your Vehicle

Overfilling your engine oil can cause excessive pressure that can lead to seal failures and leaks.

If you notice a puddle of engine oil under your car after an oil change, the oil leak could come from the dipstick compartment.

3. High Oil Pressure

High oil pressure is a sign that the engine oil is not flowing properly and is not lubricating engine parts properly.

This can cause frictional engine wear, internal engine component damage, and engine knocking in the worst-case scenario.

4. Engine Misfire, Rough Idling, and Stalling

If you overfill your engine oil by 1 liter or more, the connecting rod and crankshaft will whip oil into it, frothing the engine oil. This causes clogged plugs, rough idling, and engine misfire.

5. Oil Gauge that Wiggles Back and Forth Between Empty and Full

If your dashboard oil gauge wiggles back and forth between empty and full, you may have overfilled your engine oil. When the oil level rises above a certain level, the gauge becomes confused.

6. Engine Overheating

If there is too much oil in the engine, it will foam up and lose its lubricating power. Friction and overheating are caused by insufficient lubrication inside the engine compartment.

7. Loud Driving

An overfilled engine can make a screech, grind, or groan sound after prolonged use, which can be jarring and alarming.

8. Poor Acceleration

Excessive engine oil can creep through the piston rings and soak the spark plugs, resulting in greasy plugs and poor acceleration.

9. Car Won't Start

Whether you use synthetic or regular oil, if the spark plug is coated with too much oil and is unable to provide the spark required for the combustion process, the car will not start.

If you suspect that you've overfilled your engine oil, the best course of action is to have it drained and refilled to the correct level. Ignoring these symptoms can lead to further damage and costly repairs in the long run.

How To Check Engine Oil Levels

Checking your engine oil levels is a crucial aspect of car maintenance that every car owner should know.

It only takes a few minutes, and it can help prevent engine damage and extend the life of your vehicle. Here's how to check your engine oil levels, according to

  • Park your car on level ground and turn off the engine. Wait a few minutes to allow the oil to settle.
  • Open the hood of your car and locate the engine oil dipstick. It's usually a brightly colored handle sticking out of the engine block.
  • Pull out the dipstick and wipe it clean with a paper towel or a rag. You want to remove any oil residue from the previous check to get an accurate reading.
  • Reinsert the dipstick into the tube and push it all the way in.
  • Pull out the dipstick again and check the oil level. The dipstick has two markings for the high and low levels; the oil level should be between these two marks.
  • If the oil level is low, you'll need to add more oil. Find the oil cap under the hood, and remove it. Pour a small amount of oil into the engine and wait a few moments for it to settle. Check the level again with the dipstick, and repeat until the level is between the two markings.
  • If the oil level is high, it's crucial to remove the excess oil. An overfilled engine can cause damage to internal engine parts. To remove the excess oil, locate the oil drain plug underneath the car and use an oil drain pan to catch the oil as it drains out. Once the oil has drained out, replace the drain plug and refill the engine with the correct amount of oil.

How To Fix Overfilled Engine Oil

According to, if you have added too much oil to your car, there are a few steps you can take to fix the problem.

First, you will need to drain the excess oil from the engine. There are two common methods for doing this: using a suction pump or draining it through the oil plug. The latter method is typically easier and doesn't require any special tools.

If you choose to drain the oil through the oil plug, you will need to raise the car and place jacks under it for safety.

Then, you can locate the oil plug (using a repair manual if necessary) and remove the drain plug to let the excess oil drain into a bucket. Usually, you will only need to drain the amount you overfilled by (usually 1 quart).

After draining the oil, replace the drain plug and tighten it to specification. Finally, refit the cover (if present), lower the car to the ground, and start the engine for a few minutes before checking the oil level again.

How To Prevent Overfill Engine Oil

According to information from, it is important to prevent overfilling your engine oil in order to avoid damaging your car.

While it may be safe to add a quart of oil to most car engines, it is important not to exceed the recommended level of oil.

Overfilling can cause your engine to perform poorly, resulting in higher oil pressure and gasket leaks. This can cause premature engine failure.

To prevent overfilling your engine oil by one quart, it is best to fill your car's oil up only half a quart when changing it unless your vehicle has a very large capacity.

This helps to avoid overheating the crankshaft. If you do overfill, it is important to use a drain pan and a socket wrench to remove the oil cap and drain the excess oil.

If you need to remove more than a quart of oil, you can use a drain pan or remove the oil pan, replace the oil filter, and then drain the oil and dispose of it properly.

Checking the oil level in your car frequently is another way to prevent overfilling. If the oil pressure gauge shows unusual behavior, it may be a sign of an oil overfill, which should be removed as soon as possible to avoid damage to your engine.


Maintaining the proper amount of engine oil in your car is essential. Overfilling your engine oil can lead to a range of problems that can cause significant damage to your vehicle.

If you suspect you've overfilled your engine oil, check for the overfill engine oil symptoms we've outlined above.

By watching for these warning signs, you can catch engine problems early and prevent costly repairs down the line.

Regularly checking your engine oil levels, and ensuring they're at the right level, is a vital part of car maintenance that every car owner should prioritize.

So, take the time to check your engine oil levels regularly, and you'll be rewarded with a well-running car that will last you for years to come.