Car Oils And Fluids

What Happens If You Overfill Engine Oil?

Mike Cross
Updated Nov 18, 2020
What happens if you overfill engine oil

Have you heard the phrase: “Too much of a good thing is never good?” Well that’s certainly true when it comes to overfilling your car’s engine oil.

There is a reason why auto manufacturers recommend a specific amount of oil needed for each engine. Putting too much oil in your car’s engine can cause several issues that will eventually lead to catastrophic engine failure if not looked after.

We are going to go over some of the key problems that come with overfilling your vehicle's engine oil, how to tell if you have too much oil, and also how to drain excessive oil.

What happens if you overfill engine oil
What happens if you overfill engine oil

How much Oil?

Most car engines hold around 5 quarts of oil, but this can vary depending on the type of car you have.

The oil is in the car to lubricate the moving parts in the engine. The shafts and wheels move fast, a few thousand rotations a minute. This means a lot of heat is being produced. If you don’t have oil in your car, this heat can and will damage the engine.

Is their such a thing as too much oil though? The answer is yes there is, and as you read farther, you will learn the results of to much oil. That is why it is essential to make sure not to overfill your engine oil and also to check the dipstick after changing the oil.

What happens when you overfill your car’s engine oil?

Check Engine with Innova 3160e or 3160g
What happens when you overfill your car’s engine oil

Let’s go over some of the most common problems encountered by overfilling your vehicles engine oil so we are aware of the potential issues that this might cause to your beloved ride.

Aeration

When automakers build cars, they pour millions, if not billions of dollars in research and development to make sure they are as reliable as possible.

If you put too much oil in the engine, it’ll reach the crankshaft. When the engine is running, the crankshaft spins at thousands of times per second and it essentially turns your engine oil into whipped cream, effectively ridding it of its lubricating properties.

Excessive Oil Pressure

Too much oil equals too much pressure. Your engine is already under a lot of pressure, literally.

Having an excessive amount of oil will cause more pressure than it can handle; and the quickest way the engine can get rid of it is via various gaskets. The gaskets are engineered to only handle so much pressure. Anything over that and they start to fail, causing messy leaks and more serious issues later down the road.

Bad Fuel Mileage

Another issue caused by overfilling your car’s engine oil is decreased fuel efficiency. Too much oil will eventually make its way in the combustion chamber and get on the spark plugs. This in turn, will cause incomplete combustion and therefore affecting the fuel mileage.

Smoking

This issue could be caused by several factors including too much oil in your car’s engine. The problem with too much oil in your vehicle’s engine is that it will enter the combustion chamber and get burned with the fuel. The result is a blueish white smoke coming from the exhaust. This is also accompanied by a distinct, burnt oil smell.

Catalytic Converter Issues

Along with excessive fuel consumption and smoking, too much oil will eventually clog up your catalytic converter. The cat, as it's commonly known, is responsible for taking out pollutants from your exhaust system before it exits into the atmosphere. If the cat gets plugged, it will have to be replaced, and that is not a cheap job!

How do we Tell if the Engine Oil is Overfilled?

Check the Dipstick

The easiest way to make sure you have not overfilled your car’s engine oil is to check the dipstick.

It is important that this be done when the engine is up to operating and the car is parked on level ground. So, go out for a short drive to get everything warmed up, find a flat piece of ground, and turn the vehicle off. Pop open the hood and look for the dipstick.

If you do not know what the dipstick looks like, please consult your owner’s manual. After locating the dipstick pull it out, clean it off and insert it back into the engine for a few seconds.

Now, take it out again look to see where the engine oil level is in regard to the max fill line on the dipstick. This is usually marked by a hashed line or even words that say “empty” and “full”.

Check the Oil Level in Your Car’s Infotainment System

Most new cars have gotten rid of a dipstick and replaced it with a sensor that will tell you the oil level in your car’s infotainment system. To check this, you will have to look in your owner’s manual, as it will tell you exactly where to find it.

Have a Certified Mechanic Check the Engine Oil

If you are unfamiliar with cars, or just want to have piece of mind that everything is ok, we recommend going to a service shop and have a certified mechanic look at it. This, of course will cost you, but it's better to spend a little now, instead of potentially causing serious damage down the road

How to Drain the Excess Oil?

So, you’ve determined that there is too much oil in your car’s engine. Now what? This section is dedicated to helping you with removing excess oil from your car’s engine.

Remove it Via an Extractor Pump

If you are a backyard mechanic or just someone who has changed their car’s oil in the past, you'll know just how messy changing the engine oil can get. This is when an extractor pump comes in handy.

Its easily the fastest and cleanest method of removing that extra bit of oil. There is no more jacking up your car, fiddling with drain pans, getting your hands dirty with used oil, etc.

The only downside to this is that an extractor pump can be a little pricey, but if you are someone who does their own oil changes regularly, its well worth its price. With an extractor pump, all you have to do is insert the tube of the pump into where you add engine oil to your engine and simply turn the pump on!

Remove the Oil Via the Drain Plug

This is a traditional way of removing engine oil is via the drain plug. You follow the same steps you would when draining used motor oil. However, you must keep in mind that you are not draining all of the oil, so you should try just loosening the drain plug and not take it all the way off.  When you think enough has come out, tighten the plug, and go check the oil level on the dipstick. Repeat these steps if necessary.

Go to a Lube Shop or Dealership to Remove the Excess Oil

As we mentioned above, if you are not familiar with cars, this part is best left up to the professionals. This, of course will not be free, but its better than having an unexperienced person attempt it and potentially cause more harm than good.

Conclusion

Changing your oil is an essential part of maintaining your vehicle. The oil is what keeps the engine alive and working right.

The lubrication prevents the heat from damaging the components, and the oil carries off any metal that does wear off from the metal moving parts. Having to much oil can be just as a bad thing as not having enough though.

If the oil is overfilled and the oil gets air in it from the crankshaft, then the oil pump won’t pump it, and it will be like you don’t have any oil at all.

That is why it is essential to make sure not to overfill your oil, and if you do remove the excess, so your engine does not get damaged.

Don’t forget to leave us a comment if you have any questions about this subject or any other car related inquiries!

Mike Cross
Life is too short to drive with stock audio

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