What Causes a Crankshaft Seal to Leak?

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What causes a crankshaft seal to leak? The most common cause of crankshaft seal leak is high mileage.

Crankshaft seals are very simple components that many people do not know exist until they wear out and start to cause problems. A crankshaft seal leak, if left unchecked, can cause massive damage to the engine of your vehicle.

What Is A Crankshaft Seal?

A crankshaft seal is an essential component of an engine usually made of rubber or silicone, and metal and round in shape.

This component is attached to the front of the engine, and it seals the end of the crankshaft together with the timing cover.

What Are The Functions Of A Crankshaft Seal?

What Causes a Crankshaft Seal to Leak

Crankshaft seals are installed in the front of the timing cover to seal the crankshaft’s end as it turns to avoid metal to metal contact.

The crankshaft seal also keeps oil, which lubricates the crankshaft from leaking outside of the crankcase. This is a vital function because this oil gets tossed around continuously as the crankshaft rotates.

To better understand this function of the crankshaft seal, let us look at the crankcase. The crankcase is another component that sits below the cylinders. They help transform the engine energy into the circular motion that propels your car’s wheels to move forward.

For the crankshaft to function correctly, it must be submerged in oil and friction-free. The crankshaft seal has to keep this oil secure.

If the crankshaft seal gets cracks and starts to leak, it puts the engine at risk of significant damage if not fixed expeditiously.

What Causes a Crankshaft Seal to Leak?

Leaks of any sort, especially oil leaks in a vehicle, are common indicators of a larger problem in your car.

Like every component of a car, the crankshaft seal wears and tears and eventually gets damaged.

Crankshaft seal leak, in most cases, is caused by high mileage. For every 100,000 miles, the crankshaft seal has to be checked as it is almost, if not at the end of its lifespan.

As a car is being driven over a period of time, the crankshaft seal, just like any rubber component, can dry out and become brittle.

This can be due to the heat generated by the crankshaft or the constant friction it has to deal with from the friction between the crankshaft and the timing cover.

Apart from the wear and tear caused by heat and friction between the components, oil also degrades the car’s rubber parts over time.

When the crankshaft seal, which is mostly made from rubber, loses its elasticity, it will eventually form cracks and break.

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How Do You Know A Crankshaft Seal Is Bad?

Car components do not just go bad in one day. They gradually deteriorate until they are completely damaged. Bad or failing crankshaft seals show the following symptoms:

A High Mileage of About 100,000 Miles and Above

This in itself is not an issue but an indicator that the crankshaft seal is approaching the end of its lifespan.

Automobile manufacturers have a recommended service interval for most components of a vehicle. The service lifespan of a crankshaft seal is usually at 100,000 miles.

Servicing the crankshaft seal at the recommended service interval can prevent the seal from failing. This protects the seal and helps to mitigate the problems that may arise due to the damage.

 Oil Leaks from the Front of The Engine

Oil leakage is the most common sign that there is a problem with the crankshaft seal. If the crankshaft seal dries out, cracks, or breaks, it will likely cause an oil leak.

The leak can be small or large. Small leaks can cause the oil to accumulate underneath the engine, while a larger or more severe leak may produce a drip of oil from the engine’s front. This can be visible under the car when it is parked.

Occasional Clutch Slips

This isn’t a significant symptom of a crankshaft seal leak as it doesn’t happen often. A broken crankshaft seal may spray oil on the clutch, which can cause it to slip occasionally.

You may think this doesn’t affect you because your car is automatic. Automatic vehicles have clutches too.

Can A Broken Crankshaft Seal Be Fixed?

Can A Broken Crankshaft Seal Be Fixed

Unfortunately, no. once a crankshaft seal has cracked, it cannot be repaired. The damaged crankshaft seal has to be replaced.

Changing a damaged crankshaft seal is a herculean task because the crankshaft seal is mounted behind the engine’s main crankshaft pulley. So, servicing requires removing the belts and crankshaft pulley, and harmonic balancer before it can be accessed.

For better understanding, the following steps have to be taken to replace the crankshaft seal.

  • Raising the vehicle with jack stands
  • Removing the crankshaft damper
  • The timing belt is removed
  • The crankshaft seal is taken off and replaced
  • The timing belt and cover are replaced, and the crankshaft damper is reinstalled.
  • The engine accessory belts are reinstalled, and then the vehicle is lowered off the jack to the ground.

The steps above can take hours to achieve, so I am sure you do not want your crankshaft seal to deteriorate to the point it may stop you in the middle of the freeway on a road trip.

For this reason, if you suspect your crankshaft seal may be leaking or has gotten to the end of its service life, have your car inspected by a professional technician.

Do not subscribe to quick fixes such as mixtures to add to oil to stop your crankshaft seal from leaking. There are no miracle products you can add to your oil that can permanently stop an oil leak. These products, when used for long periods, can severely damage your engine.

If you must use them, let it be short-term until you can replace the damaged crankshaft seal, this should be just a couple of days.

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As simple as a crankshaft seal is, it plays a significant role in the overall functioning of your car’s engine.

It is crucial that you note the service intervals and closely monitor the car’s mileage, especially vehicles in constant use. A damaged crankshaft seal spells doom for the engine.

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