Overfilling Engine Oil by 1 Quart – What Happens?

When it comes to changing and topping up your car’s engine oil, you must pay attention to it, but after doing it a few times, you may find yourself paying less attention.

It is possible to overfill your engine with too much oil, so should you worry about that? Too much oil can cause high oil pressure which can lead to gasket and seal leaks.

When there is too much oil, it will aerate and cause foaming and frothing, which reduces the lubrication of the engine.

If overfilling your engine oil by 1 quart is something you should avoid, and how to spot when your engine has been overfilled and needs fixing, then this is for you.

Engine Oil

Do I Need To Worry About Overfilling Engine Oil By 1 Quart?

Ensuring good levels of engine oil is an essential part of any car maintenance. If you overfill your engine oil, what do you do?

It is recommended by the manufacturers that you clean, cool, and lubricate the moving parts of your engine to prevent them from seizing or leaving you with a broken vehicle.

If your vehicle has an oil-level gauge on your dashboard, you will need to use the dipstick under your bonnet to check the levels.

If you accidentally overfill your engine oil, it can cause it to overflow and leak into other areas of your vehicle such as the transmission or power steering pump that are adjacent.

Extra strain on your vehicle can be caused if you put too much oil in your engine, it can cause more gas to be burnt, and even promote excessive carbon buildup on the pistons, making it harder for you to drive.

If you want to avoid a breakdown, high gas consumption, damaged electrical components and increased wear and strain on your engine then you should try to overfill your engine oil by 1 quart.

Can I Slightly Overfill Engine Oil?

Some general rules apply to a wide range of cars that make it easier to figure out if you have overfilled or underfilled engine oil.

It is recommended that you don’t overfill your engine oil by more than 1 quart as this generally works out as a 20% overfill on your engine oil levels and the general recommendation across all vehicles is that you shouldn’t overfill above that

The safest thing you can do to avoid engine damage is to drain your engine oil, if you notice foam on your dipstick, or if there is excess oil above one quart.

Symptoms of Excess Engine Oil

There are some obvious signs that your vehicle may have an issue with the amount of oil in its engine if you suspect that you have put too much oil in your engine.

If your engine oil is overfilled then this could cause your vehicle to break down.

  • Have a burning oil smell.
  • Illuminate the Oil Pressure Light.
  • Smoke coming from your engine bay.
  • Smoke from the exhaust.
  • Leak oil due to overflow.

Removing Excess Engine Oil

If you are comfortable doing an oil change on your own, you will most likely be able to drain excess oil as well. You can always get a mechanic to do this for you if you aren’t able to.

If you want to suck away excess engine oil but don’t want to leave any aerated oil in your engine, then a fresh oil change is the best way to go.

Before you start, make sure the vehicle has not been started and is cold to reduce the risk of burning yourself, and have something ready to collect your used oil.

  • You should put your container under the oil pan to catch the old oil.
  • The drain plug needs to be removed from the bottom of your oil pan.
  • Once empty replace the drain plug and the oil filter.
  • You should refill your engine with the correct amount of oil according to your owner’s manual.


Will an Extra Quart of Oil Hurt?

Adding half or quarter quart of oil to your engine shouldn’t cause any issues and in many cases, an entire quart will be harmless too, but there is always a risk that if your oil levels get high enough this can interfere with

How Much Oil Overfill Is Safe?

Adding an extra 20% of oil to your vehicle is safe. Make sure you regularly check your engine’s oil levels to make sure it is in good condition and not negatively impacting the health of your vehicle, this usually works out as 1 quart of oil.

Will Excess Oil Burn off?

If you have excess oil in your engine, it can cause serious issues. To prevent damage to your engine, you should remove the oil and replace it with the right levels.

Can an Overfill of Oil Blow a Head Gasket?

If your vehicle is drinking oil and burning up your cash, this may be a sign that your head gasket is blowing.

Engine Oil


Getting the right amount of engine oil in your car is important to maintaining the function and movement that your engine needs to run smoothly.

A small amount of excess engine oil is an easy mistake to make and usually will not cause any problems or concerns, but overfilling engine oil by 1 quart or more can be dangerous.

Your manufacturer’s recommended engine oil levels are designed to promote the optimal performance in your vehicle and you risk creating a shorter life span for your engine and are at an increased chance of your vehicle breaking down if you overfill.

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