Overfill Engine Oil Symptoms: What happens if you put in too much oil?

Changing the engine oil of a vehicle is also an important task for maintaining its overall health. It is one of the most common vehicle servicing tasks that are carried out to maintain the hassle free functioning of the engine. 

Routine maintenance can help the vehicle withstand minor deformities within the engine, but fresh engine oil is always its best friend. You will possibly experience a change in performance after replacing the burnt and old engine oil with that of the fresh oil. 

But as the experts are concerned, too much engine oil can possibly damage the engine’s core. Moreover, it can also increase the damage potential and eventually the cost of repair. Therefore, the technicians believe that excessive engine oil should be removed immediately. 

But how does the excessive engine oil cause any damage? What exactly happens if you do it by mistake? All of the answers are mentioned within this detailed explanation on overfill engine oil symptoms. 

How Much Engine Oil is Too Much?

How Much Engine Oil is Too Much

Overfilling the engine oil above the maximum given level will trigger the possibility of serious damage to the engine. If the oil level is slightly above the maximum line, you do not have to do anything over the line to drain it, as the engine can manage that little excessiveness. 

To help you with numbers, if you have filled the engine with oil above 0.3 inches of the maximum mark, you should drain out some extra oil. The maximum engine oil capacity should be around 4 to 5 quarts. But, you should still check your car’s engine manual to determine the actual capacity. 

The oil doesn’t drain from the engine! Therefore, you should consider filling the engine oil compartment to 3-quarters of the available capacity to avoid overfilling. The engine oil reserve in a vehicle holds a little extra oil as per the maximum mark to compensate for the fluid expansion aspects during a hot climate. 

As per the car types are concerned, the 4-cylinder unit engine will require only 3 quarts of oil, and a large 6-cylinder engine will need around 6 quarts of oil. So, the amount of maximum oil levels for a vehicle engine depends upon the engine size. 

Therefore, anything too above the maximum mark in the engine oil reserve can cause serious damage to the engine functionality! You will know more about it later in the article! 

What Can Happen if You Put Too Much Engine Oil in Your Car?

A vehicle engine comprises a lot of mechanical parts and precision-crafted elements. All of them work altogether to give the vehicle power for seamless functionality even at high temperatures. When the temperature rises, the engine parts need proper lubrication in order to ensure smooth movement. 

Therefore, adding or replacing engine oil over time is important for a vehicle’s running life. But that doesn’t mean you should empty the whole lubricant bottle in your vehicle reserve that you just purchased. It will overfill the reserve, and you will have to bear the consequences, such as:

1. Frothy Oil

When you add too much engine oil to your vehicle, the excessive oil will move towards the crankshaft. And when the crankshaft rotates at high speed, the oil will be mixed with air and aerates. As a result, the oil will become foamy. 

This foamy texture in the oil is accountable as a bad lubricant for the engine, and it doesn’t pump effectively within the engine to serve its purpose. Over time, the engine will crave proper lubrication. Without timely check and maintenance, the weak oil pumping aspect will get the engine locked up permanently, resulting in expensive repair costs. 

2.  Too Much Pressure

The tail and head couplers and the crankshaft end stop prevent oil leakage conditions. Putting too much engine oil on the engine will increase the overall pressure on these components. As a result, there will be possible oil leakage within the engine. Moreover, if the oil leakage occurs around the flywheel of the vehicle, then it can contaminate the clutch system and possibly cause damage. 

While the crankshaft whips the oil, it will produce air into oil, increasing its volume. Hence, this is how the pressure increases within the system. The seals and gaskets are accountable for preventing the oil from going back to the areas they shouldn’t go! Due to over-pressurizing, the seals and gaskets will give up their ability to prevent oil from leakage. 

The front and rear seals of the crankshaft are difficult to access and replace! Therefore, overfilling can be a serious problem regarding pressure within the system and oil leakage scenarios. 

3.  Spark Plug Issues

Spark Plug Issues

The excessive oil leak out can come in contact with the spark plugs. Once the oil coats the plugs, they can no longer receive a high voltage pulse for initiating the spark. Apart from that, this might also trigger the inability of the spark to jump the gap and initiate the combustion process. 

The fouled spark plugs can trigger engine misfires and might cause the vehicle to go dead. If this problem occurs, then excessive oil filling might be one major cause of it. But, spark plugs are easy to replace if anything like this happens in your vehicle. 

4.  Catalytic Converter Issues

Catalytic Converter Issues

A catalytic converter aims to reduce the toxicity percentage of exhaust gases. The catalytic converter heats up when the vehicle runs for a long time. If any oil reaches the combustion chamber or farther into the exhaust system, it might burn upon reaching the catalytic converter. 

If the oil burns within the catalytic converter, it will deteriorate its ability to clean and detoxify the exhaust gases. As a result, it might also shorten its life of seamless functionality! You should keep in mind that the catalytic converters are pretty much expensive to replace. 

In worst cases, the catalytic converter will get clogged when it comes in contact with excessive oil. Hence, this can be dangerous as the exhaust system can heat up excessively and might even start a fire. 

Overfill Engine Oil Symptoms

Now that you are aware of the issues that you can face due to excessive filling of engine oil in your vehicle, it is time you should know the vital symptoms of it as well. If you are filling your engine oil all by yourself and are not aware of the maximum mark, then it is possible that you have overfilled it by mistake. 

But, how to realize if that is hampering your vehicle? How to know if your vehicle needs servicing? You will have a better knowledge upon reacting to the vehicle conditions when you are aware of the overfilling engine oil symptoms. The symptoms are:

  • Visible oil leakage out from the engine oil reserve compartment of the vehicle. 
  • The strong burning smell of the engine oil. 
  • Smoke signs from the engine bay. 
  • Smoke signs from the exhaust area. 
  • Too much noise emission from the engine. 
  • Engine Oil Pressure Light will be triggered ON over the dashboard. 

How to Remove Excess Oil from Your Engine?

When the engine is filled with extra oil, it is time for you to drain it out. There are two different ways for you to do this: 

Using Oil Suction Pump

It is the first method that is less messy and easy to adapt. You will need the oil suction pump, with which you will be pumping the oil from the cap access point and dipstick tube. You do not have to raise the car, but you will need an air supply for the vacuum. For this process, you can prefer to use both an automatic as well as a manual vacuum pump. 

Using Drive Socket Wrench and Plastic Oil Pan

It is the traditional way of draining excessive or complete engine oil. This is an easy but messy method for you to adapt. You will need the drive socket wrench and plastic oil pan for this purpose. For the purpose, you will have to raise your car or vehicle to a certain height, and then you will have to crawl underneath it to locate the engine oil reserve plug. 

Now, place the plastic oil pan beneath that plug and loosen it. Loosen it with the drive socket wrench until the oil starts to drip. Do not loosen the plug too much, as it will increase the flow of eradicating the engine oil. Therefore, loosen it a little and just eradicate a little oil out to maintain the levels. Now, check the dipstick again to ensure that the levels are right. 


If you are not experienced in opening up the engine oil reserve valves or using the suction pump, it is better to get help from a technician or mechanic. Do not approach it all by yourselves, as you might make things messy or might also drain out excessive engine oil and set it below the minimum mark. 

You should consider maintaining the proper engine oil levels without overfilling or underfilling the reserve. It will ensure seamless engine functionality and smooth running of the vehicle.

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