What Happens If I Overfill My Oil?

by Synthetic Oil | Last Updated: April 30, 2023

Adding oil to your car’s engine is an essential step in routine maintenance. However, there are accidents you can make that may impact the performance of your vehicle, such as overfilling the engine with oil. If you accidentally overfill the engine oil, it can lead to some serious problems. Today, we are going to explore what could happen if you overfilled your car’s oil, as well as how to tell if there is too much motor oil in your car, and how you can correct this mistake.

**Note** – A quick hello to anyone reading this, I’m Alastair and this is my site Synthetic oil.me. I started this site to help people with their oil questions, and hopefully what you’re about to read will help answer your questions. This page may include affiliate links to the likes of Amazon, which if you make a purchase I qualify to earn a (typically small) commission. Don’t worry as this won’t cost you anything, the likes of Amazon pay any commissions. Thank you in advance for your support as this helps bring you more (hopefully) helpful content.

What Happens If You Put Too Much Oil In Your Car?

While an overfill of engine oil may seem like a low-risk issue, it can, in fact, cause a number of problems. Too much engine oil is certainly too much of a good thing. If you put too much engine oil in your car, it can cause the oil to foam up (from the crankshaft making contact with the oil), which can lead to reduced oil pressure and inadequate lubrication. This can cause excessive wear and tear on your engine’s bearings and other moving parts, leading to engine damage and potential engine failure.

Of course, simply overfilling your engine may cause high oil pressure—which is a problem you do not want.

One of the potential consequences of high pressure from an overfilled engine is oil leaks. When there is too much oil in the engine, it can cause pressure to build up in the engine’s oil passages, which can force oil to leak out through gaskets and seals. Why? Because the pressure has to go somewhere. This can cause oil to leak onto your engine, which can lead to a fire or other serious damage. Leaks in the engine bay can also cause smoke.

In addition to engine damage and oil leaks, overfilling your engine oil can also lead to decreased fuel efficiency. When there is too much oil in the engine, it can cause the crankshaft to rotate through the excess oil, which creates more drag and resistance. This extra resistance can cause your engine to work harder than it needs to, which can lead to decreased fuel efficiency and increased emissions.

How to Determine if Your Engine Has Too Much Oil

To determine if you have an overfill of engine oil, you’ll need to check the oil level on the dipstick. Start by turning off your engine and letting it cool down for a few minutes (5-15 minutes is good enough). Then, locate the dipstick, which is usually located near the front of the engine and has a brightly colored handle. Pull the dipstick out and wipe it clean with a rag or paper towel.

Insert the dipstick back into the engine and then pull it out again. Look at the end of the dipstick that was inside the engine to see where the oil level is. There should be two marks on the dipstick, one for the minimum level and one for the maximum level. If the oil level is above the maximum mark, then you have too much oil in your engine.

Car Symptoms of Having Overfilled Engine Oil

If you’ve accidentally overfilled your engine with oil, you may notice a number of symptoms. The most common symptom is that the engine may start to run poorly or even stall. This can be due to the excess pressure inside the engine, which can cause the valves to stick and the piston rings to lose their seal. You may also notice that the oil pressure gauge is higher than normal.

Another symptom of too much oil is that the engine may start to smoke or emit a strong burning smell. This is due to the excess oil being burned off inside the engine. When this happens, it can cause carbon buildup and other problems. In addition, the smoke and burning smell can be a sign that the excess oil has caused damage to the catalytic converter or other emissions components.

Other symptoms include:

• Reduced fuel economy
• Decreased engine performance
• Engine damage or failure
• Engine knocking or rattling

If you happen to notice that your car is displaying these symptoms, don’t wait. Check the oil level as soon as you can. If the oil level is excessive, you are going to need to remove some of it.

How to Remove Excess Oil From Your Engine

If you’ve determined that your engine has too much oil, the first step is to drain the excess oil from the engine. How? The same way you change the oil. Lift the car off the ground, if necessary. Locate the oil drain plug. You can usually find that at the bottom of the engine oil pan. Use a wrench or socket to loosen the drain plug. From there, let the excess oil drain into a container.

Since stopping the flow of oil is going to be difficult, perform a fresh oil change. That will ensure you put the correct amount in. Otherwise, you may have to continue the draining process over and over, which can be messy and difficult.

If you do not feel comfortable performing your own oil change or applying this fix to an overfilled engine, consider taking your vehicle to a qualified mechanic.

Are There Other Options For Removing Overfilled Engine Oil?

If you would prefer to remove the excess and not waste your time and money on a fresh oil change (especially after just doing one), there are a few other methods you can employ.

One method is to use a fluid extractor or oil suction pump to remove the excess oil through the dipstick tube. These tools work by creating a vacuum that sucks the excess oil out of the engine and into a container. This method is often used by professionals and DIY enthusiasts alike because it’s quick and easy and doesn’t require you to remove any parts or drain the entire oil pan.

This video explains how to make a siphon with an air hose and syringe, which essentially works the same way as the vacuum mentioned above:

Final Thoughts on Overfilled Engine Oil

Overfilling engine oil can be a serious problem with terrible consequences. Reduced oil pressure, inadequate lubrication, engine damage, diminished fuel efficiency, and engine damage are all possibilities. It’s important to always follow your car’s manufacturer’s recommendations for the correct amount of engine oil to use and to regularly check your oil level to ensure that it’s within the appropriate range. If you do accidentally overfill your engine oil, it’s important to take immediate action to remove the excess oil and avoid driving your car until the issue has been resolved. By being proactive and taking proper care of your car’s engine, you can help ensure that it stays in good condition and continues to run smoothly for years to come.