Car Leaking Oil After Oil Change: Fixed!

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. 

The most common cause of a car leaking oil after an oil change is a loose drain plug. If the drain plug is not properly tightened after the oil change, it can cause the oil to leak from the car. It is also important to ensure that the oil filter was also tightened correctly after you change the oil. Another possible cause of a car leaking oil after an oil change is overfilling. If too much oil is put into the car during the oil change, it can cause the oil to leak out. Another reason for a car leaking oil after an oil change is a faulty oil pressure sending unit. This unit is responsible for monitoring the oil pressure in the engine and can become damaged over time. Lastly, the oil pan could be cracked or rusted, or the gasket could have shifted while changing oil. If the gasket does not seal the connection between the oil pan and the engine, it will cause oil leaks after oil change.

Bonus Read: Oil leaks when car is parked

Table of Contents

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 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.

If the oil level is low or the pressure is low, then you should definitely not drive with an oil leak. The oil is necessary for keeping the engine lubricated and running smoothly. 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

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. 

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

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 spot?

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

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. The oil filter is installed in the oil line and filters the oil as it circulates, making sure the oil is free of debris.

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 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.

I have shown both configurations of the oil filter in the picture below:

configurations of installation of oil filter

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. You should remove the old gasket. 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

The drain plug is a plug that 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 crush washer of the drain plug of the oil pan while tightening. It is usually recommended to get a new drain plug as it’s difficult to find a new seal/washer for the drain plug when it is untightened while changing the oil.

drain plug of oil pan

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

While changing the oil, the oil pan has 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.

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.

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
  • Oil pan bolts should meet torque specifications

When it comes to maintaining the oil pan of your engine, two key steps are essential: degreasing the mating surface and prepping the drain hole threads. To degrease, use a reliable engine degreaser and a lint-free towel to clean the mating surface of the oil pan.

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.

Then, apply a thin bead of RTV silicon sealant to the gasket to adhere it to the oil pan. Make sure that you don’t use too much sealant – a little goes a long way. 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. If it moves, you will need to give the sealant more time to hold.

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 will 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.