Behind the Scenes: Unveiling the Jeep Wrangler Rear Main Seal Leak

The rear main seal of the Jeep Wrangler is responsible for sealing the engine oil inside the engine so that it doesn’t leak from the crankshaft to the transmission. 

There are various possible reasons that can leak the rear main seal of the Jeep Wrangler. A rear main seal can leak when the engine is running low on engine oil because due to low engine oil, the engine will overheat causing the rear main seal to lose its temper and leak. Also, broken main bearings and imbalanced flywheel or flexplate can contribute to the leaking of the rear main seal. 

Additionally, the wrong installation of the main bearing, crankshaft, or flywheel can lead to a rear main seal leak because they will function inadequately. Moreover, a rear main seal can naturally wear out after reaching its operational life. 

What Are the Symptoms of Jeep Wrangler Rear Main Seal Leak?

The symptoms that indicate the Jeep Wrangler rear main seal is leaking from it are given below.

Engine Oil Leaking: A puddle of oil will leave a mark on the ground where you have parked your vehicle. Though the oil can leak from various places of the engine but in the case of a rear main seal leak, the oil will leak from the middle or rear of the engine where the engine connects to the transmission. 

Engine Oil Reducing: The engine oil will reduced severely and the “check engine oil light” will illuminated on the odometer. Frequently you need to fill up the oil to maintain the accurate engine oil level. 

Engine Performance Dropping: The performance of the engine will drop intensely due to a lack of engine oil and the vehicle will overheat within a short period of time when driving. 

Check Engine Light On: Check engine light generally pops up on every problem but it can also happen due to a real seal leak of the Jeep Wrangler. 

What Causes Jeep Wrangler Rear Main Seal Leak?

Jeep Wrangler’s rear main seal can leak due to low levels of engine oil, the main bearing might be broken, the flywheel or flexplate misaligned, the installation of the rear main seal is improper, and natural wear or tear of the rear main seal. 

1. Low Engine Oil

When the engine of the Jeep Wrangler is running low on oil, it will generate more heat because the components of the engine will have more friction between them. As a result, continuous overheating of the engine can melt the rubber-made rear main seal, causing it to leak. 

2. Broken Main Bearings

The main bearing of the Jeep Wrangler holds down the crankshaft so that it can rotate in a fixed position. As both are made of metal, the rotation of the crankshaft can break the main bearing due to friction over time. 

When the main bearing is broken, the crankshaft will be in an upright position which will strain the rear main seal and the oil can leak from it. 

3. Imbalance Flywheel or Flexplate

The flywheel or flexplate is attached to the Jeep Wrangler engine crankshaft. It becomes imbalanced due to various reasons. Over time, the crankshaft can become damaged or worn out causing it not to rotate freely which misaligns the flywheel or flexplate position. Also, the flywheel or flexplate can be imbalanced when it is cracked or broken after reaching its operational life. 

When the flywheel or flexplate becomes imbalanced, it puts extra pressure on the rear main seal causing it to stretch and oil leaking. 

4. Improper Installation

Improper installation of the main bearing, crankshaft, flywheel, or rear main seal can cause the oil to leak. It occurs when the rear main seal is replaced before and sometimes, mechanics unintentionally make the mistakes when installing. 

The possibility of improper installation is high for DIY repairs because the process of replacing the rear main seal is complex and needs a high level of skills and knowledge. 

5. Worn-Out Rear Main Seal

It is common that the rear main seal of the Jeep Wrangler will be worn out naturally just like other things. Mainly, the rear main seal wears out when the crankshaft rotates against the seal, and over time, it deteriorates. Also, it can wear out when the vehicle is running high on mileage. 

When the rear main seal worms out, the engine oil will slowly leak from the engine block. 

How to Fix Jeep Wrangler Rear Main Seal Leak?

You have to replace the rear main seal in order to fix the Jeep Wrangler rear main seal. You can follow the steps below for DIY repairs. 

  • Lift the vehicle on a jack to get access under the vehicle and drain the engine oil by removing the drain plug and keep it somewhere safe to reuse it if it’s new or you can change the engine oil. 
  • After draining the oil, detach the oil pan from the vehicle, you may need to lift the exhaust or adjust it, depending on the model of the Jeep Wrangler.
  • Once the oil pan has been detached, you have to remove the bearing cap brace and the main bearing cap by twisting it front and back to loosen it. 
  • Then, pull out the front half part of the seal from the block but before taking it out, you should take extra precautions because a single dent or scratch can damage the surface and it will no longer be repairable. Also, take note of the orientation of the seal before taking it. 
  • Clean all the oily residues from the main bearing cap with a toothbrush and grease. Make sure to clean it thoroughly because one small residue of the old seal can cause it to leak. Also, clean the engine block from where you have removed the bearing cap. 
  • Install the front half part of the seal by placing the seal opening toward the front of the vehicle and lubricate with engine oil while installing. You cannot use any kind of sealant on the engine blocks.
  • Then, install the remaining half part of the seal into the main bearing cap by applying sealant. Add some engine oil to the bearings. 

However, be noted that replacing the rear main seal of the Jeep Wrangler is very complicated and time-consuming. You have to be highly skilled and need the necessary tools and knowledge to do it accurately. 

If you do not have past experience, it is best to address the issue at any authorized service point or professional mechanic to do the job for you. 

Should You Replace or Repair Jeep Wrangler Rear Main Seal?

You should not repair the Jeep Wrangler rear main seal because repairing will not provide a permanent solution. Yet, if you repair the seal, it will not last longer because the residue of the old sealant will hamper the seal causing it to leak within a short period of time. 

It is advisable to replace the rear main seal with a new one because it’s a labor-intensive job and the time and effort you are giving should come in value. Besides, replacing will provide you with a permanent solution and at least you can drive the vehicle around 8000 miles or 13000 kilometers before thinking of replacing it unless something unusual happens. 

How Much Does It Cost to Repair a Rear Main Seal on a Jeep Wrangler?

The cost of repairing the rear main seal on a Jeep Wrangler depends on many factors. The cost varies on different models, years, and whether the model comes with manual or automatic transmission. Also, the cost can vary on the part number of the specific model and from where the service has been taken from. 

Even though the price range of the rear main seal of the Jeep Wrangler is inexpensive and it comes within a price range of $15-$30. However, the labor cost is highly expensive and needs much time and effort. Usually, the average cost of repairing the rear main seal of a Jeep Wrangler comes in between $600-$1000, including the labor and product cost. 

How Long Can I Drive With a Rear Main Seal Leak?

Technically, you can drive the Jeep Wrangler with a rear main seal leak. However, it depends on the condition of the leak that how long you can drive. In case of a slow leak, you can drive the vehicle but you have to keep an eye on the engine oil level and needs to top up when the engine oil gets low. 

On the other hand, if the oil leaks excessively from the rear main seal then, you really should not drive the vehicle at all. The engine can seize in no time due to overheating, leaving you with the additional cost of repairing the vehicle. 

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