How to Tell If Your Rear Main Seal Is Leaking

mechanic looking for a leak, How to Tell if Your Rear Main Seal is leakingIf you’re wondering how to tell if your rear main seal is leaking, then your vehicle must be leaking something.  Before we get into the technical details of determining if you’ve got a rear main seal leak versus another type of oil leak, we need to be sure that it is indeed oil that your vehicle is leaking, not power steering fluid or transmission fluid or some other type of lubricant.  To be sure you’ve got an oil leak, try checking out our article on how to determine what your car is leaking.

Once you’re sure you’ve got an oil leak, we can help you figure out whether it is the rear main seal that is leaking or some other oil seal or gasket in your engine.

How to Tell If Your Rear Main Seal Is Leaking

  • Are there any higher oil leaks?
  • Are there drips from the bell housing?
  • Is the oil pan gasket leaking?
  • Is the flywheel or flexplate oily?

Since rear main seal leaks are uncommon on most vehicles it’s very possible that you’ve got another leak higher up on the motor that is dripping down and just looks like a rear main seal leak.  The most common leaks that can masquerade as a rear main seal leak is a valve cover gasket leak, intake manifold gasket leak or a distributor gasket leak.  If you find oil on your engine above the bellhousing, check for leaks at these locations.  If you find one, repair it, clean the engine and check for leaks again in a few hundred miles.

A rear main seal leak will cause oil to drip from the bottom of the bellhousing at the front of the transmission.  If you have drips coming from in front of the bellhousing, locate those leaks, stop them and clean the engine. After a few hundred miles you can check again for leaks to see if you still have any.

The most common leak that is confused as a rear main seal leak is an oil pan gasket leak at the rear of the engine.  The oil pan gasket is just below the rear main seal. An oil pan gasket is also usually much less expensive to replace so it’s important to check for leaks in your oil pan gasket before you jump to any conclusions.

The best way to prove that you’ve got a rear main seal leak is the check if the engine side of the flexplate or flywheel is oily.  If the rear main seal is leaking on your engine it will drip oil onto the flexplate or flywheel and sling oil around the bellhousing. Most engines have an inspection cover in the bellhousing the allow you to check for this.  If you find oil on your flywheel or flexplate, use BlueDevil Rear Main Sealer to restore your rear main seal and stop your leak.
BlueDevil Rear Main Sealer


You can find BlueDevil Rear Main Sealer at any of our partnering local auto parts stores like:

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  • Consumer Auto Parts

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leak_repair,jpg – By Welcomia – Licensed by Getty Images – Original Link

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