Rear Main Seal Leak Symptoms And Repair Cost

If you notice huge oil puddles underneath your car while taking it out of the garage, it is a serious concern that needs to be checked immediately. The main culprit for this leak is damage to the rear main seal. 

The gaskets and seals must be in good working condition for your car’s crankshaft to function properly. The main aim of the rear main seal is to seal off the transmission and the engine block and keep the motor oil from spilling.

Furthermore, these components make sure that your engine is properly lubricated. If this seal gets damaged, you will notice oil leaking onto the ground. 

The best way to fix this is to take your vehicle to the local auto repair center and get the damaged seal replaced.

But, how much should you fork out to repair the faulty seal? Keep reading to get a better insight into the signs of rear main seal leaks and if it is possible to get it fixed without emptying your wallet.

Rear Main Seal Leaks: An Overview 

The rear main seal consists of a thick rubbery gasket, placed in between the transmission and the engine block, to prevent the motor oil from escaping.

Though the gasket is made of rubber, it plays an important role in properly sealing the engine. In this manner, the seal prevents oil leaks and keeps hazardous engine situations at bay.  

When the leak goes unnoticed, your engine runs out of lubricating oil, creating friction between the engine parts. This friction can cause extensive damage to your cylinder walls and bearings.

Due to the leak, adequate motor oil will not be available for certain integral engine parts. Eventually, the damage will be huge, resulting in the escalation of the rear main seal replacement charges. 

For vehicles with a manual transmission, motor oil leaks from the engine can be quite hazardous. Especially if you’re driving on a dirt road, the lubricating oil on the ground can cause a slippery effect.

It also reduces the wheels’ traction on the ground causing you to lose control of your vehicle, leading to accidents. If you ignore this issue and the oil keeps leaking from the engine, it can cause a catastrophic effect leading to complete damage to your engine. Nobody wants that to happen. 

Signs of Faulty Rear Main Seals 

The best way to resolve rear main seal leaks is to look out for oil spots underneath your car after parking it somewhere for some time. Based on how often you take your vehicle for a ride, the oil leaks get larger over time.

To avoid causing any damage and escalating the repair works, it is better to get it fixed as soon as possible.

You will notice some common signs if your rear main seal gets damaged. 

1. Oil Spots

Extensive oil consumption is the early signal that indicates your rear main seal is defective. Subsequently, you will notice oil leaks under your car after parking it for a few hours.

Initially, only a few droplets start dripping from the engine, causing the leak. When left unnoticed, the leak escalates, creating larger oil puddles that can cause damage to the other parts over time. 

2. Frequent refilling

A defective rear main seal will result in a large amount of motor oil leaking from the engine within a short time. In some cases, the damaged seal can leak up to a liter of engine oil within a week.

The rapid oil loss calls for frequent refills to prevent the motor oil from dropping to extremely low levels, which can be dangerous. 

Though it’s normal to top-off small quantities of motor oil from time to time, constantly having to refill is a red flag indicating the worn-out rear main seal. Take the time to assess the cause of the leak and get it fixed soon.

3. Burning oil smell:

When the rear main seal gets damaged, oil starts dripping in small quantities and sticks to the engine parts. This eventually starts burning when the engine operates at high temperatures.

It also gives off a pungent burning oil smell which becomes more evident once you drive your car. 

The burning smell becomes more intense when the leaking oil enters the exhaust system and burns when it comes in contact with the hot exhaust parts. If you delay the repair work, you will have to pay more to get it fixed. 

How Much Will It Cost To Repair The Rear Main Seal Leak?

As the rear main seal plays a crucial role in ensuring the motor oil remains safe within the engine, you need to get it fixed quickly if you notice oil leaks or puddles below your car. Typically, you will have to replace these seals when they get damaged. 

Unfortunately, when it comes to rear main seal repair works, it is one of the most expensive vehicle repairs you will encounter.

Though these components do not cost more than a few hundred dollars, the labor costs can easily go above $1000, making the rear main seal repair quite expensive.

Why is it Expensive?

The mechanics charge around $500 and $2000 for the labor charge alone in certain places. The high repair charges are related to the demanding labor. Normally, it takes around 8 – 10 hours to fix the leak and get the engine back on the road.

As the mechanics have to invest a lot of time to fix the rear main seal leaks, you will end up having to leave your car in the repair shop for a few days. 

Repairing the rear main seal of your engine is a complex task where the transmission has to be removed to access the gasket.

While repairing four-wheel vehicles, you will also have to remove the transfer case to repair works. This is why it is not possible to replace the rear main seal on your own in the garage.

Final Thoughts

Though replacing the rear main seal can be quite expensive, you will have to get it done as soon as possible to avoid causing any damage to the transmission and other engine parts. Motor oil leak is a red flag indicating a serious issue. If ignored, it can cause total engine damage. As oil is essential for the engine’s smooth operation, any form of oil leak must be addressed soon.

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.