Put Too Much Oil in Your Car Engine? (Here’s What to do)

It's a very common mistake to overfill motor oil because it's difficult to know exactly how much oil to add for the perfect level. Here is what you should do if you make this mistake

Overfilling Engine Oil

Your engine oil light appears on your dashboard when you are on the way to an important meeting.

You purchase 2 liters of engine oil and pour it all into your engine. You check your dipstick and realize that you have overfilled the oil above the MAX sign on the dipstick.

What to do now? Will my engine get damaged because of too much oil in the engine?

In this article, you will learn what will happen if you overfill the engine oil and learn what to do about it.

What Happens If You Overfill Oil?

Overfilling engine oil far above the max level can cause serious damage to your engine. Luckily, there is no need for action if the oil level is slightly above. But if you filled it 0.3″ or more above the sign, it is time to drain some of the oil.

The engine oil reserve holds some extra oil to compensate for the fluid expansion due to hot conditions. Adding an extra half a quart will not damage your engine. However, anything more than that could be harmful to the engine.

When you add too much oil, the excess oil will go towards the crankshaft, and as the crankshaft rotates at a high-speed, the oil is mixed with the air and ‘aerates’ or becomes foamy. This foamy texture of the oil acts like a bad lubricant, and the oil is not pumped effectively. Over time, the engine will be starved of proper lubrication, and due to the weak oil pump, it can get locked up.

Overfilling Engine Oil

RELATED: Will a Slight Overfill Harm an Automatic Transmission?

Causes of Overfilling Engine Oil

Check Engine Oil

If you noticed that your engine oil is above the max-sign on the dipstick even if you are sure that you did not overfill the engine oil, there is one big reason for this.

If you are only driving short distances, the fuel in the combustion chamber will slowly fill up the engine oil pan with fuel and therefore increase the oil level.

When you drive long distances and the engine becomes hot, this fuel will evaporate out from the engine oil. This can be solved by taking your car out for a long drive.

If it is very much above the max-sign, I do recommend an oil change instead.

Symptoms of Excess Engine Oil

Sometimes you do not know if you or the mechanic have overfilled your engine oil. But if you have some of these symptoms, there might be a risk that your engine oil is overfilled.

  • Oil leakage
  • A burning smell of engine oil
  • Signs of smoke from the engine bay
  • Signs of smoke from the exhaust area
  • Engine making too much noise
  • Engine Oil Pressure Light on Dashboard

How to remove excess engine Oil

Drain Engine Oil

Now that you know that the engine is filled with extra oil, it is time to drain the excess oil. There are two ways to do this: the first method is easy and less messy. It requires an oil suction pump through which you pull the oil from either the cap access point or the dipstick tube. This method does not require you to raise your car, but you will need an air supply for the vacuum. You can use both a manual vacuum pump or an automatic. If you want a manual tool for these tasks, which is also good for several other things, check out the: Vacuum Fluid Extractor Pump Tank Remover Link to Amazon

The second method is traditional and can be messy. The tools required are a drive socket wrench and a plastic oil pan. Raise your car to some height, then crawl underneath and locate the plug. Place the plastic oil pan beneath the oil plug and loosen the plug until the oil drips. Don’t loosen the plug too much and remove only a certain amount. Check again with the dipstick to ensure the correct amount of oil.

Note: Some vehicles have a cover under the car that has to be removed before you can reach the oil plug.

RELATED: Should You Check the Engine Oil Hot Or Cold?

How much Engine Oil should I fill in my car?

Most engines require 3 to 8 quarts of oil, but it varies depending on the engine’s size. For example, a 4-cylinder unit will require 3 quarts of oil, whereas a larger 6-cylinder engine may need approximately 6 quarts of oil. You can also find more information about your engine’s oil capacity in the owner’s manual. Always be careful that you fill in the right amount.

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Written by:

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.