Can Oil Leak Cause Alternator Failure? Effective Fixing Steps

The alternator is a vital component in a car due to its responsibility of charging the battery as you drive. The part also powers most of the electrical systems in the vehicle. Therefore, an alternator failure can be a serious problem. However, the big question is – Can oil leak cause alternator failure?

Yes, an oil leak can cause different types of car problems, including alternator failure. Engine oil or power steering fluid leaking on the alternator can cause it to overheat or short circuit, leading to failure.

oil leaking on alternator

A leaking oil can introduce dirt or debris into the alternator, causing it to wear out or malfunction. Fortunately, a defective alternator can be repaired. This article reveals how oil leak can trigger alternator failure and how to fix the problem.

Can Engine Oil Leak Cause Alternator Failure?

Yes, an engine oil leak can cause alternator failure when the leaking oil seeps into the alternator and cause a short circuit. When the leaking oil enters the alternator, it can cause the part to overheat and eventually fail.

Here’s what happens if oil gets on alternator. If oil enters your car’s alternator, a lubricating coating forms on the slip rings and the brushes.

As a result of the brushes being abraded, a mass forms, resulting in poor contact or short circuits. This automatically causes the alternator to fail. In addition, premature wear is also imminent due to the brushes softening.

So, if you suddenly experience electrical malfunctions, battery drain, or difficulty starting your car, you most likely have a bad alternator. You may be wondering, “Can oil damage alternator?” Of course! However, some other vehicle problems can also trigger an alternator problem.

That’s why you must carefully diagnose the issue to find out the actual cause of the problem. An alternator covered in oil can be frustrating to deal with. Nevertheless, the problem is not insurmountable.

Besides oil leaking on alternator, a sudden failure can also be caused by several other vehicle problems. While some are relatively cheap to repair, others can be quite expensive, depending on the level of the damage.

Other Causes of Alternator Failure

Apart from oil in alternator, some other causes of alternator failure include; a blown fuse, incorrect use of jumper cables, overloading, wiring problems, dead battery, and corrosion. Here’s a more detailed explanation of the issues listed above.

Blown fuse

The alternator fuse is designed to break the circuit whenever too much current flows through it. Therefore, a blown fuse will automatically shut down the alternator and alter the power supply to other electrical components.

Incorrect use of jumper cables 

When jump-starting a car, connecting the jumper cables wrongly may cause an electrical current surge that could damage the alternator or other delicate parts.


Overloading the alternator is one of the most common causes of failure. This is usually the result of higher than normal electrical loads in the car, such as running headlights, power windows, using the radio, running the AC, and other electrical systems simultaneously.

Wiring problems

Several wires synergize in producing power supply to the alternator. If one or more of these wires are disconnected or cut, the power supply process would be interrupted, thereby resulting in alternator failure.

Dead battery

A dead car battery can also lead to alternator failure. A car’s battery is designed as a power bank that supplies power to various electrical systems. If the battery is completely dead, the alternator would be overstressed, thereby causing the component to fail.


Typically, alternators are designed with splash-proof. However, if the splash-proof is absent and there’s extreme water infiltration when washing your car’s engine with a steam jet, the ingress can result in corrosion of the terminals and contacts.

Driving through large puddles can also cause water to flood the alternator, thereby causing corrosion, softening the carbon brushes, or damaging the ball bearings. These can also lead to alternator failure.

What Part Most Commonly Fails in an Alternator?

The most common part to fail in an alternator is the rotor bearings. The bearings are designed to allow the rotor to spin freely within the housing. Unfortunately, they can break down at any time due to exposure to dirt and heat.

Other parts that can also fail easily in the alternator include the voltage regulator, brushes, and diode. That’s why it is vital to ensure that you properly diagnose a failed alternator to ascertain the exact problem or faulty part before attempting to repair the component.

How to Repair Alternator Fail Due to Oil Leak

Once you diagnose the actual cause of your car’s alternator failure, fixing the problem becomes easy. If you’re experiencing an alternator failure due to an oil leak or power steering leaking, the following recommendations will help you fix the problem.

Inspect internal parts

Loosen the alternator and examine the components to see the damaged part. Check the brush, the amateur, the rotor bearing, and other components. Replace any damaged component.

Clean up oil residue

Clean the alternator and its surrounding thoroughly with a degreaser to remove any oil residue. This will prevent further damage from occurring, which may damage the new parts you installed.

Test the alternator

Now it’s time to test the alternator to make sure it’s working perfectly. Mount the alternator following the reversed process. After that, start your car and allow it to run for a while; then, observe the alternator’s operation in charging your car’s battery and supplying power to the electrical systems.


An alternator failure can ultimately keep your car grounded if not rectified as soon as possible. Paying attention to the causes of alternator failure listed above and doing everything possible to avoid such an occurrence would save you both money and stress.

However, if you’re already battling an alternator failure and you suspect that an oil leak is responsible, ensure to fix it ASAP. Meanwhile, if you have a buddy who’s asking, “Can oil leak cause alternator failure?” kindly recommend this article to them.


Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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