Why is My Car Leaking Oil After an Oil Change?

A loose or faulty drain plug, improperly tightened oil filter, overfilling the engine oil, a malfunctioning oil pressure sending unit, or a cracked oil pan are common causes of leaking oil from car after oil change. Ensure the drain plug and oil filter are tightened properly and the correct amount of oil is added during the oil change. Also inspect the oil pan gasket seal. Properly diagnose and repair oil leaks to avoid further engine damage.

It’s no surprise that as a responsible car owner, you’ve heard of the importance of regular oil changes and followed through with one recently. You may have even done it either yourself or at the dealership!

But, it can be a shock to come home and see a puddle of oil oozing from your car. Let’s start by addressing the most common causes of oil leaks after an oil change, so you can get your vehicle back in good health. 

Bonus Read: Oil leaks when car is parked

To enhance your troubleshooting of the oil leaking issue, I have provided below some essential concepts. These concise sections will aid your comprehension of the topic before delving into the various causes of oil leakage.

However, if you just want to jump to the causes of oil leaking after oil change click here.

Some Key Insights for You
  • Oil leaks after an oil change can happen due to residual oil, overfilled engine oil, improperly installed filter, loose drain plug, damaged gasket, or using the wrong oil grade.
  • It’s safe to drive with a minor leak if oil level and pressure are okay, but leaks should be fixed soon to avoid engine damage.
  • Loose drain plugs, crushed gaskets, uncleaned mating surfaces, overtightening, and reuse of old parts can prevent proper seals after an oil change service.
  • As engines age, switching to thicker oil can reduce leaks from worn seals.

My Personal Experience With Car Leaking Oil After Oil Change?

Last year, I noticed a small puddle of oil forming under my car after an oil change. Concerned, I immediately checked the dipstick and saw the oil level was fine.

I crawled under the car and discovered the leak was coming from a loose drain plug.

I tightened it with a wrench and added a new crush washer for good measure. No more leaks! Proper diagnosis allowed me to quickly fix the oil leak myself without costly repairs.

Bonus Read: You can also read my guide on causes of check engine light after oil change.

Visual Inspection Of Oil Leak Or Dripping

Before you investigate the reasons behind oil leaking after changing oil, you should first confirm that it is actually engine oil and not something else.

Oftentimes, people mistake engine oil, transmission oil, brake oil, and coolant.

So, if the color of liquid leaking from car while changing oil is:

  • Brown/golden or black: It indicates engine oil.
  • Blue, orange or green: It indicates engine coolant.
  • Reddish or red-brown: It indicates transmission oil.
  • Brake oil: Almost the same color as engine oil i.e. beige or yellow color. It also gets dark brown/black with time.

Is It Safe To Drive With An Oil Leak?

The short answer is, yes, it’s safe to drive with an oil leak but some conditions must be met in order for this to be a safe option. First, you need to make sure that the oil level is between the upper and lower marks on the oil dipstick. You can do this by removing the oil dipstick, wiping it off, and then reinserting it. If the oil is too low, it can cause serious damage to your engine.

The next you thing to consider is the oil pressure from the oil pressure gauge on the dashboard.

You should make sure the oil pressure is within the manufacturer’s specifications. If there is not enough oil pressure, it will affect the lubrication and damage the crankshaft bearings.

Without the proper amount of oil and pressure, the engine will overheat, seize, and can cause serious damage

Causes Of Car Leaking Oil After Oil Change

Here are the causes of the car leaking oil after oil change:

1. Residual Oil After Changing Oil

Residual Oil After Changing Oil

When you change the oil in your car, there’s always some residual oil left on the sub-frame or splash shield from the oil change.

This oil can also settle around the drain plug and oil filter, and if it isn’t completely wiped off, it can start to drip down onto the ground and create the appearance that your car is leaking oil. 

How to fix residual oil after oil change?

To fix a residual oil leak, you need to thoroughly clean the area around the oil drain plug and oil filter. You can do this using a rag and some oil-dissolving cleaner, such as brake cleaner or engine degreaser.

Be sure to wipe off any excess oil or dirt that may have collected on the underside of the vehicle or around the drain plug.

It’s important that you take the time to make sure that all residual oil is removed. Even if you think you’ve done a good job, it’s always a good idea to double-check, just in case. 

After cleaning the oil thoroughly, park the car on the cardboard for some time to see if any oil spill occurs.

2. Engine Oil Is Overfilled

a funny animated illustration showing Engine Oil Is Overfilled

Engine oil overfilling is exactly what it sounds like: adding too much engine oil to your vehicle.

It is important to understand why overfilling your oil can be so detrimental to your vehicle.

The motor oil in your vehicle is designed to lubricate the metal parts as they move against one another. If too much oil is added, however, it can be dangerous

Furthermore, when too much oil is added, the level in the oil pan becomes too high. That allows a fast-moving lobed rod called the crankshaft to come into contact with the oil and foams it up, which increases the pressure in the engine.

This pressure pushes oil out of the engine past the gaskets and seals, creating an oil leak. 

How to determine that engine oil is overfilled?

A person overfills the engine oil when he/she does not know the exact quantity of oil required by the engine.

Before adding engine oil, you should always check the engine oil level when the engine is cold. This is because when the engine is heated, the oil expands and becomes thinner.

So, if you do not properly check of engine oil level, you’ll overfill it. When the engine is cold, the oil level should be between the upper and lower marks on the dipstick.

When changing the engine oil, make sure to check the owner’s manual for the recommended amount of engine oil needed, including the oil filter.

Avoid mixing old oil with new oil as it can affect the accuracy of the amount required.

If you do mix, take note of the amount of old oil and add it to the new oil. Keep in mind that the engine oil capacity stated in the manual is only accurate if the oil pan is drained completely, and the old oil filter is replaced without adding in any old oil.

How to know how much oil is in the engine?

To know how much oil is left in the engine before filling it with the oil, you should keep in mind that the engine oil dipstick does not touch the bottom of the oil pan.

When the oil dipstick is bone dry, your engine still might have 1 to 2 quarts of oil left. Usually, the high/low marks on the dipstick are a quart or less apart.

3. Improperly Installed Oil Filter

configurations of installation of oil filter

An oil filter is a replaceable cartridge installed in the engine of your vehicle that keeps small particles and debris from getting into the engine and causing damage.

If the oil filter is not properly installed while changing the oil, it can cause the oil to leak out around the filter.

This is because when the oil filter is installed, it’s supposed to create a tight seal with the gasket. If the filter is not on straight, it won’t create a tight seal and the oil will leak out. 

In such cases, the size of the oil filter matters a lot. If the aftermarket filter size is incorrect, the oil filter may not properly seat on the mounting surface. 

The configuration of the oil filter fitting depends on the type of engine. In some engines, an oil filter is fitted into the engine block through an adapter. In other engines, the oil filter is directly bolted into the engine block.

Furthermore, while replacing the oil filter, most people forget to remove the old gasket that usually sticks to the engine block. 

If you accidentally use two gaskets while installing the oil filter, they will blow out due to excessive pressure and cause oil leakage after changing oil.

So, you’ve to make sure that there is only one gasket of the oil filter while installing it. Sometimes, the old gasket sticks into the engine block where the oil filter is mounted. So, you have to check that.

You can check out the below video from 5:00 time. That guy has explained in detail about the leakages through the oil filter.

4. Drain Plug Is Not Properly Tightened Or Crush Washer Is Missing

Drain Plug Is Not Properly Tightened Or Crush Washer Is Missing after oil change

The drain plug runs into the oil pan. To change the oil, we have to remove the drain plug to drain out the old oil from the oil.

After changing the oil, the mechanic usually makes a mistake while tightening the drain plug. If the drain plug is over-tightened, it will squish the copper washer out of shape.

Moreover, if the drain plug is loose, the oil pan gasket will not be properly pressed against the engine block to seal the mating surface of the oil pan.

Lastly, mechanics forget to put the new crush washer of the drain plug of the oil pan while tightening. The old washer/seal of a drain plug can’t seal the gap properly between the drain plug and the oil pan. So, a new washer for the oil pan is necessary.

5. Oil Pan Gasket Is Not Properly Seated

oil pan gasket is not properly seated or damaged

While changing the oil, the oil pan may need to be removed and cleaned before adding new oil. The oil pan gasket is also removed to clean the mating surface of the oil pan (the surface on which the gasket sits).

This is because the sludge of old engine oil and carbon is deposited on the mating surface that must be cleaned. And this is only done by removing the oil pan gasket.

If the gasket of oil pan is damaged, you should use an OEM-recommended oil pan gasket. Don’t go for cheap aftermarket alternatives.

Before installing the oil pan gasket, you need to do the following steps:

  • Mating surface of the oil pan is clean
  • Mating surface of the oil pan is not warped
  • RTV sealant should be applied on the mating surface of the oil pan. After mounting the gasket to the oil pan, allow some time for the adhesive to set. To test for slippage, press on the gasket lightly.
  • Oil pan bolts should meet torque specifications

To install a new oil pan gasket, use the engine degreaser to clean the mating surface of the oil pan, and remove foreign particles, such as RTV, dirt, and oil. If the mating surface of the oil pan is not cleaned properly, it will not seal the gasket.

For chrome-plated oil pans, brush out the threads of the drain hole to remove any flakes that could potentially lead to a leakage. Furthermore, you may need to tap around the bolt holes of the oil pan for further preparation. By following these steps, you’ll ensure a safe and effective seal of your oil pan.

When it comes to checking if the mating surface of an oil pan is warped, two tools are necessary: a straight edge and a feeler gauge.

using straight edge to check flatness of mating surface of the oil pan

Begin by placing the straight edge along the flange that contacts the engine block. Take the feeler gauge and pass it under the straight edge, looking for any gaps wider than 0.1mm. If you detect any warping, you will need to bend, pound, or hammer the oil pan until it is even.

6. Using Of Incorrect Visocity Grade Of Oil 

Oil viscosity is a measure of the oil’s resistance to flow, which directly affects its ability to lubricate engine parts and is an important factor in determining the oil’s suitability for a specific engine.

Many modern cars require a specific viscosity grade of oil, but it’s important to note that, as cars get older and rack up more miles, the viscosity grade of oil recommended may change. 

As engines age, the engine seals tend to wear out and clearances between engine components also increase.

This increased wear can be minimized by switching to a thicker, higher viscosity oil, such as 5W-30 instead of 5W-20. This thicker oil is better able to fill any gaps between the moving parts and reduce wear.

So, if your engine is older and you continue to use thinner oil i.e. 5W-20, it will start leaking through engine seals and spacing between engine components.

Furthermore, if you’ve been using conventional engine oil till your engine gets older, and then you switch to synthetic oil in your recent oil change, it may leak out through engine seals.

Synthetic oil is slightly thinner than conventional oil and has excellent detergency. The cleaning property of synthetic oils washes sludge and carbon deposits around seals that accumulated over time and prevented oil leakage. After the sludge washes out, a gap will be created around the seals and cause oil leakage.

How Long Does It Take To Fix An Oil Leak?

The answer to this question depends on a few things. The first is the severity of the leak. In some cases, a minor oil leak can take as little as thirty minutes to fix.

This might involve tightening a loose oil pan or oil filter. changing a small gasket, or replacing a seal. If the oil leak is more severe, it can require more time.

For example, replacing an oil pan gasket or valve cover gasket may take more than 4 hours to fix oil leakage.

Preventing Oil Leaks

Preventing oil leaks in your vehicle requires attention to detail and a proactive approach. Here are a few essential steps you should note in your vehicle maintenance schedule checklist:

  1. Inspect Seals and Gaskets: Periodically inspect the seals and gaskets in your engine for signs of wear or damage. These components play a crucial role in preventing oil leaks. If you notice any cracks, leaks, or deterioration, it’s important to replace them promptly.
  2. Use High-Quality Oil and Filters: Opt for high-quality engine oil and filters that meet the specifications recommended by your vehicle’s manufacturer. Quality products can provide better protection and help maintain the integrity of seals and gaskets.
  3. Be Mindful of Oil Changes: During oil changes, ensure that the old oil filter is properly removed and replaced with a new one. Additionally, make sure the drain plug is securely tightened to prevent oil from leaking out.
  4. Avoid Overfilling: Overfilling the engine with oil can lead to excessive pressure, which may cause leaks. Follow the recommended oil capacity mentioned in your vehicle’s manual and pour the oil carefully.
  5. Monitor Warning Signs: Pay attention to any warning signs of potential oil leaks, such as oil spots under your vehicle, a burning smell, or low oil pressure warnings on the dashboard. If you notice any of these signs, have your vehicle inspected by a qualified mechanic.

Autocornerd team has made a tool for vehicle maintenance schedule lookup. So, be sure to check that out.

Some First Hand Experiences Shared By Users In Different Communities

Our team conducted research across various online communities, forums, and subreddits to gather user comments and opinions on “car leaking oil after oil change”.

User 1 says:

Just had an oil change on my Sonata last week, and noticed a small puddle of oil underneath the next morning. Turned out, the oil filter wasn’t tightened properly. A quick trip back to the mechanic, and it was sorted with no further issues.

User 2 says:

Had a similar issue with my F-150. The oil leak turned out to be due to a cracked oil pan. I only noticed it because of a strange smell and a small patch of oil on the driveway. Replacement wasn’t cheap but necessary.

User 3 says:

After an oil change in my Renegade, I started noticing oil spots on the ground. The service center had installed the wrong oil filter, leading to a leak. They replaced it at no extra cost, but it was an inconvenience.

User 4 says:

My Lexus RX started leaking oil after a recent oil change. I was initially puzzled but later realized the oil drain plug was not properly seated. It was a simple fix but a reminder to double-check the work done during maintenance.

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