Oil Leak On Alternator [Why + How To Fix]

Most of the time, worn-out seals are the main reason for the oil leak on alternator. The oil seal is basically rubber that acts as an alternator oil drip guard. However, there can be other reasons, like:

  • A damaged gasket.
  • Cracked housing.
  • Or an engine overfilled with oil. 

So, if your car is not functioning the way it used to, then an alternator oil leak is often the culprit you can blame. No matter how good your car is, it will have some pitfalls. And oil leaking on alternators is one of them. 

oil leak on alternator

In that context, we will explore the possible causes of oil leaks on alternators, their symptoms, and how to fix them so that you can have the best driving experience with your car.

So, let’s get started…

Oil Leak On Alternator Seal [Why + How To Fix]

Before knowing the causes and their fixes, it is crucial to know the signs of oil leaking on alternators. There are a couple of ways to tell if the alternator seal is faulty or not. Perhaps, the following warning signs should concern you:

01. Oil Leaks

Is your car’s alternator leaking oil? If so, then your alternator is probably damaged. In fact, this is one of the most common signs that your alternator is failing. Additionally, you may notice a pool of brown fluid at the front of your car if you leave it for a while.

02. Engine Overheat

Another common symptom of an oil leak on an alternator is an overheated engine. If the oil starts to leak, there won’t be enough oil to lubricate the parts that are continuously moving. At some point, the engine will overheat due to excessive friction.  

03. Failure In Electrical Components

The alternator plays a vital role in powering the electrical system of the car. If there is a leak on the alternator, the electrical operations may fail due to not getting power. If oil gets inside the computer unit, you will need to replace it. Replacing the computer unit can be expensive.  

04. Dead Battery

Just like the electrical components, the alternator is also responsible for providing the necessary power to charge the battery. If the alternator is covered in oil due to a leak, it won’t function properly. As a result, the battery may not get sufficient charge.  

05. Burning Smell

Due to an oil drip on alternators, it can come close to the heated parts of the vehicle. So, you will smell burning oil while driving the car. Moreover, blue-tinted smoke coming from the exhaust is a sign of an oil leak. 

06. Engine Check Light is On

Although several factors may cause the dashboard check engine light to illuminate, it can also happen when an alternator seal problem causes oil to leak into the alternator. Unlike the other signs, this is not common for an alternator oil leak. Still, you can’t ignore it.

Causes Of Oil Leak On The Alternator And Their Fixes

Before getting into the main reasons behind oil leaks in alternators, make sure you’re not mistaking the powering steering pump for an alternator. They look roughly the same and often share the same location. So, many people mistake the hydraulic fluid of the pump for engine oil.

With that said, there are several causes for an oil leak on the alternator. The severity of these factors may vary depending on the model and type of your vehicle. After a comprehensive analysis, we have found that the following reasons are the main culprits of oil leaks on alternators:

1. Worn Out Seals

The most common cause of an oil leak on the alternator is worn-out seals. The seals around the alternator can wear out eventually due to aging. Additionally, exposure of the seals to high temperatures can lead to oil leaks. 


Replacing the worn-out seals would be better than repairing them. You can easily replace them by getting help from a mechanic. The process involves removing the alternator from the engine and replacing the seals with new ones. 

2. Damaged Gasket

Sometimes, you may notice the valve cover gasket leaking on alternators. It indicates the gasket that seals the alternator to the engine can be damaged, which is causing oil leaks.


The only solution to the issue is to replace the damaged gasket with a new one. The process can be a bit complex to do on your own. Therefore, you should hire a mechanic to remove the alternator from the engine and then replace the old gasket with the new one.   

3. Cracked Housing

Exposure to high temperatures can damage the housing of the alternators. Also, physical damage can cause cracks in the housing. In both cases, it will lead to an alternator oil leak. 


Fixing the cracked housing may solve the problem. However, it is better to replace the cracked housing entirely for a permanent solution.

car damaged housing

This will involve removing the alternator from the engine first. Then, replace the damaged housing with a new one. 

4. Overfilled Engine Oil

Is your alternator covered in oil? That is because you probably overfilled it. Overfilling the engine oil can cause oil to leak out of the alternator seals and gaskets. This can build excess pressure on the serpentine belt to prevent generating enough power to work properly. 


If the oil leak is due to overfilling the engine oil, you can easily fix the issue by draining the excess oil to the correct level.   

How To Clean Alternator From Oil

There are various ways to clean an alternator. But how to clean an alternator? Or can you clean an alternator? Fresh water can be a good option for cleaning alternators. 

A smart decision would be to take out the alternator from the engine and disassemble it for cleaning. Use soapy water to thoroughly clean each part of the alternator.  While cleaning your alternator, use a soft brush to wipe it down. 

clean the alternator from oil

If this doesn’t work for you, then use alternator spray cleaners. You can use WD40 on alternators for this. Before cleaning an alternator with WD40, disconnect the battery. Then, apply a small amount of WD40 onto a clean cloth and gently wipe the exterior of the alternator. 

Clean the vents with a soft brush. Finally, dry the alternator completely before reconnecting the battery. 

After cleaning, leave the alternator to dry. It is always wise to disconnect the battery before cleaning and then reconnect it once you are done cleaning. 

Simply replacing the alternator is preferable when it is pretty old. Before doing this, make sure the valve cover gasket has been changed. Otherwise, you risk experiencing the same problem shortly after installing the new gasket. 

The following video will give a better insight into how to clean an alternator from oil,

What Causes Coolant Leak On Alternator

There are many possible reasons for causing a coolant leak on alternators. The problem can be as annoying as an alternator oil leak. Here are some possible causes of this issue:

i). Leaking Water Pump:

The water pump plays a vital role in circulating the coolant through the engine. If this pump is leaking, it can allow coolant to leak onto the alternator.

ii). Damaged Intake Manifold Gasket:

The manifold gasket is responsible for sealing the intake manifold of the engine block. If this gasket is corroded or damaged, coolant can leak from the intake manifold and eventually onto the alternator. 

iii). Rusted Engine Components:

Rust or corrosion on engine components can cause coolant leaks. If such components are located above the alternator, then coolant can leak onto the alternator. 

iv). Improperly Installed Gasket:

If the gasket is installed in a way that damages it, then it may fail to seal the engine block to the intake manifold. Therefore, the coolant may start to leak. 

Additionally, if the cylinder head is not installed correctly or is damaged, it can cause coolant leaks. 


Can an oil leak cause alternator failure?

Yes, an oil leak can cause alternator failure. If oil leaks onto the alternator, it can damage the internal components and cause them to malfunction or fail. Also, oil can affect the electrical wiring, leading to issues with the charging system. 

Can oil leak after changing the alternator?

It is very uncommon that changing the alternator could cause an oil leak. However, if the mechanic accidentally damages the gasket or an oil line while replacing the alternator. Other issues may also cause this coincidentally. 

What happens if oil gets on the alternator?

It can cause damage to the internal components, though; it will depend on the amount of oil. The alternator can overheat or malfunction if it gets oiled. If you notice oil on the alternator or suspect an oil leak, you should inspect and fix the problem immediately. 

Is oil on the alternator belt dangerous?

If oil drips on the alternator belt, it could make it slippery. If it slips as you rotate the steering wheel, then it can become challenging to turn it for not getting enough power. Therefore, it can be dangerous.  

How long do alternators last?

In general, a car alternator lasts about 7 years. An average alternator will run well without any problems until it covers 80,000 to 150,000 miles. 

Bottom Line

We assume you have learned the causes of an oil leak on alternators. Additionally, if you have read this far, you should have known the symptoms and the fixes to solve this issue. So, you must have found the answer to the question, “How to clean oil off alternators?” 

To conclude, we suggest cleaning an alternator regularly with clean or soapy water. This will enhance the lifespan of the alternator. Let us know if you have any queries on how to protect an alternator from oil; we will be glad to answer them.

Note: Read our ultimate guide on why alternator smoking when i hook up a battery and how to fix it.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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