Why Do I Have a Leaky Rear Main Seal?


Leaky Rear Main SealHaving a leaky rear main seal can put you in a tight spot.  Do you let it leak? Do you get it fixed? Do you sell the car and pass the problem on to someone else?  Before you decide, it’s important to understand how you got here and what your options are.

Why Do I Have a Leaky Rear Main Seal?

  1. High mileage
  2. Low oil level
  3. Extended time not running
  4. Installation error
  5. Poor seal design

Like any part in your car, lots of miles take a toll.  The rubber seal is sealing against the spinning crankshaft and metal beats rubber every day.  No matter your make or model, enough miles will cause your rear main seal to start leaking.

Any part of your engine will get worn out more quickly without enough oil.  Your rear main seal is no different and low oil levels can quickly lead to a leaky rear main seal.  

When your engine isn’t running, the crankshaft drags the rear main seal down just slightly.  If it’s left like that for too long the seal will stay stretched out even after you start the motor and that stretched seal will be leaky.

If you’ve recently changed your rear main seal and it’s still leaking it’s possible that the seal was installed incorrectly.  Rear main seals are often very large seals and can be very difficult to install evenly around the crankshaft. If you’ve got the seal installed correctly, it’s also possible that the old seal wore a groove in the crankshaft and you need a crankshaft repair sleeve to stop the leak.

If you’ve done some research about your vehicle specifically, you may have noticed that your particular make and model is prone to having a leaky rear main seal.  Some rear main seals tend to leak due to their design and if this is the position you’re in, oftentimes replacing the seal will only buy you a few leak-free miles if that.

If this is the position you’re in, the hard part repair might not make sense.  In these situations, the best thing to do is use BlueDevil Rear Main Sealer to stop the leaky rear main seal and keep your car on the road.

You can pick up BlueDevil Rear Main Sealer at one of your local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • CarQuest Auto Parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Canadian Tire
  • Walmart

Pictures Provided By:

rear_main_seal.jpg – By FabrikaCr – Licensed By Getty Images – Original Link

2 responses to "Why Do I Have a Leaky Rear Main Seal?"


  1. Andy on March 30, 2020 at 12:43 pm

    Where can I get the 32 oz bottle of rear main seal

    • BlueDevil Pro on March 30, 2020 at 3:44 pm


      The BlueDevil Rear Main Sealer only comes in an 8 oz. bottle. One bottle would treat up to 8 quarts of oil. We do not manufacture a 32 oz. bottle of Rear Main Sealer.

      Thank you!


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