Have you ever overfilled your car with oil? If you did, you would probably know that you did, due to the smoke coming out of the engine. While most people know that too little oil can damage their vehicle, the consequences of putting too much oil in your car are also incredibly damaging if left untreated.
You can put too much oil in your car, as it can result in costly damage to vital components like your spark plugs, gaskets, catalytic converter, and, of course, the engine itself. Additionally, the crankshaft will aerate the excess oil, turning it into a foam that cannot lubricate your car properly.
If you or your mechanic has overfilled your car with oil, don’t panic. Keep reading to learn more about why your car needs oil, how much your specific vehicle needs, and what you should do to remove excess oil after an overfilling incident.
Fill Your Car With the Appropriate Amount of Oil
Most vehicles need anywhere from 3 to 8 quarts of oil to run properly and keep the engine and surrounding parts adequately lubricated.
However, the precise amount your car needs will vary depending on the make and model, so you will likely have to check your owner’s manual to be sure you’ve filled it with the correct amount of oil.
You can also check your car’s dipstick to get an idea of your car’s exact fill level. The dipstick will have an “add” line and a “max” line, and your car’s oil level will need to be somewhere in between the two levels.
Be sure to check your dipstick while your vehicle is on flat ground and the engine has cooled off to get an accurate reading. It might be best to check it first thing in the morning, before you start it, as that will give you a more accurate reading.
A slight overfill of a few millimeters or so is usually not a cause for alarm. If you drive your car normally, the small amount of extra oil will burn off by itself.
However, if the reading on the dipstick shows your car has been overfilled by 0.3″ (7.62 mm) or more, you will need to remove the oil or do a fresh oil change to mitigate the issue.
Why Your Car Needs Oil
Your car’s engine consists of an array of interacting metal parts that move and collide with each other at very high speeds and very high temperatures.
To prevent all of these metal pieces from grinding against each other, wearing away, and causing damage to your car’s engine and its surrounding components, your car needs oil to act as a lubricant.
The oil sits in an oil pan while your vehicle isn’t running. Every time you turn on your car, the oil begins circulating throughout the engine and eventually passes through an oil filter that removes metal shavings and other contaminants.
Too much, too little, or poor-quality oil can quickly cause severe issues for your vehicle, which is why getting regular oil changes and frequently checking your car’s oil level are so important. While it is common knowledge that not enough oil will damage your car’s engine very quickly, overfilling it with oil also presents a wide range of costly issues.
You should develop a habit of checking your car’s oil level often, particularly after an oil change.
How To Know if You Put Too Much Oil in Your Car
The quickest way to determine if you have overfilled your car with oil is to check the dipstick. As we touched on earlier, your dipstick will have an “add” and a “max” line, and the oil level should sit comfortably between the two levels.
If the oil exceeds the “max” line, you may also see a foamy substance on the dipstick, which is a clear sign that your vehicle’s crankshaft has already interacted with the oil. The crankshaft rotates at high speeds, and if your car has too much oil, it will essentially whip air pockets into the oil, turning it into foam.
The oil can’t lubricate your vehicle correctly if it has developed this foam-like consistency, so keep an eye out for it on your car’s dipstick. However, if your car is so old that the dipstick holder fell off and you no longer have a dipstick, you might want to take your car to a mechanic to make sure you’re not overfilling it, or get a different car.
Other symptoms that your car has been overfilled with oil include:
- White or bluish smoke from your vehicle’s exhaust, usually a sign of burning oil.
- Oil leaking onto the ground into a puddle when your car is parked.
- A bitter, sour, burning scent from your vehicle’s engine.
- Oil pressure indicator lighting up or giving a high-pressure reading.
- Unusual sounds coming from your engine.
- Engine stalling, missing or running “rough,” which is usually a sign your spark plugs have been coated in excess oil.
What Happens if You Overfill Your Car With Oil?
There are many issues associated with leaving too much oil in your car that can cause very costly and, in severe cases, irreparable damage over time.
The excess oil can stress your vehicle’s seals and gaskets that work to prevent the oil from leaking out from the engine and coating nearby parts. As the pressure builds on the gaskets and seals, they can fail, necessitating expensive replacements.
Additionally, your car’s spark plugs can become coated in oil and damaged, which can eventually cause your engine to misfire, stall, or not start entirely.
The spark plugs will then be unable to generate the initial spark needed to power your car.
As your car’s crankshaft becomes coated with excess oil, it will rotate at high speeds, mixing air into the oil and turning it into a foamy mess. The frothy consistency essentially makes the oil useless, depriving your engine of adequate lubrication.
It is best to check your vehicle’s oil level often so you can remove any excess oil immediately to prevent these issues.
How to Remove the Excess Oil
You have a few options when it comes to getting the extra oil out of your car. Each method involves draining out the oil to bring the level back down to an acceptable range, in turn preventing the oil from leaking out or damaging your vehicle’s components.
Keep in mind these can be a bit messy if you attempt them yourself.
Method One: Use a Vacuum Pump
This method to remove excess oil from your engine is a bit simpler than the second option, but it requires the use of a rather pricey vacuum oil extractor pump like the OEMTOOLS Oil Extractor available on Amazon.
The best part about this method, despite its cost, is that you don’t have to raise your car or get under it to remove the oil.
Basically, the vacuum pump works by using a long straw that goes into your car’s dipstick tube and siphons out the oil. This method can be tricky if you aren’t an experienced mechanic, so we don’t recommend it to the typical layman.
If you are in the process of buying a pump, make sure you check out our article on the best oil extractors available right now.
Method Two: Loosen the Oil Plug
You also have the option to loosen your car’s oil plug and allow the excess oil to drain out into a drain pan, but this will require you to raise your vehicle. However, this option is less expensive than the other two, making it more convenient for the average driver.
You will need a jack to raise your car and a wrench to carefully loosen the oil plug. Get underneath the car and let around a cup or two of oil seep out at a time, being careful to measure the amount of oil you’ve drained.
After draining the right amount of oil, tighten the oil plug and start the engine to move the oil around for a bit. Let your car’s engine idle for a few minutes before turning it back off to let it cool.
Finally, check the reading on your dipstick while your car is on level ground after it has cooled down. You’ll need to wipe it off and then put it back in to get an accurate reading. Ideally, your car’s oil level will now be within an acceptable range.
If it’s too low, you can always add more.
Method Three: Oil Change
The most reliable way to get rid of excess oil in your car is to perform an oil change, either on your own or with the help of a mechanic.
To perform an oil change on your own, depending on your car’s make and model, you’ll generally need to do the following:
- Take off the oil drain plug at the bottom of the oil pan and let all of the oil drain out.
- Dispose of your old oil filter and replace it with a new one.
- Check your owner’s manual for exactly how much oil your vehicle needs.
- Refill the oil with the amount directed by your owner’s manual.
Many vehicle owners aren’t comfortable with changing their own oil. If you don’t think you can do it on your own, seek the help of a reputable mechanic rather than attempting it yourself. They have access to the best tools and can get the job done in less than 20 min.
Your vehicle needs plenty of oil for lubrication, but too much can seriously damage many of your car’s more costly parts if you don’t remove the excess. Be sure to always keep your oil level well within the “add” and “max” lines to keep your engine running smoothly.
Thankfully, if you or your mechanic overfills your car with oil, you have several options to remove the excess oil and prevent it from leaking out from the engine. If you aren’t comfortable draining the extra oil yourself, seek the help of a professional or change the oil entirely.