Rear Engine Oil Leaks – Finding The Real Location Of The Leak

Rear Engine Oil Leaks - Finding The Real Location Of The Leak
Rear Engine Oil Leaks - Finding The Real Location Of The Leak

Rear engine oil leaks that are confused with a rear main seal leak are usually an oil pan gasket leaking.

Consequently, An oil pan gasket is also much less expensive to replace than a leaking rear main seal.

So, It’s important to check for leaks in your oil pan gasket before you jump to any conclusions.

Rear Engine Oil Leaks - Finding The Real Location Of The Leak
Rear Engine Oil Leaks – Finding The Real Location Of The Leak

But before you panic, you’ll want to check other options higher up that may be dripping down.

The most common rear engine oil leaks that can masquerade as a rear main seal leak are:

Valve Cover Gasket Leak
Valve Cover Gasket Leak

So, If you find oil on your engine above the bellhousing, check for leaks at these locations first.

If the rear main seal was leaking on your engine it will drip oil onto the flexplate or flywheel. Most engines have an inspection cover in the bellhousing that will allow you to check for this. The best way to prove that you’ve got a rear main seal leak is; to check if the engine side of the flexplate or flywheel is oily.

Consequently, Almost 90% of all rear main seal oil leak complaints, were actually leaks in the pan gasket, rocker covers, side covers, etc., and are not leaking rear main oil seals.

Rear Main Seal Leak
Rear Main Seal Leak

Finding The Actual Location Of Rear Engine Oil Leaks

The Following Is A Suggested Procedure To Determine The Exact Location Of The Leak:

  1. Wipe the underside of the engine to clean all dirt and oil from the oil pan, etc.
  2. Plug breather pipe and oil filler opening with rags.
  3. With the engine idling, blow compressed air into the dipstick pipe or opening.
  4. Watch for oil leak and trace to the source.
  5. Determine whether the oil is coming from the pan gasket, pan gasket end seal, leaky fitting, rocker cover gaskets, push rod cover gasket, or from any source other than the rear main oil seal.
  6. A small mirror and flashlight are handy tools to use in checking hard to see places.
The rear main seal is in a position that; you won’t be able to just slide under your car and see it. As a result, You need to go through a process of elimination. If you seem to be losing oil but you don’t have a noticeable drip when the car is parked; you may be in the early stages of a leak.

Start the vehicle up and let it idle for 15 minutes and see if that helps you identify the leak; or at least begins to show some oil leaking in the engine. Once you’ve determined you’ve got a dripping leak, you’ll want to start from the bottom and work your way up.

Rear Camshaft Plug Leaking
Rear Camshaft Plug Leaking

Consequently, If you see oil dripping on the back of your oil pan; or on the front of your transmission bell housing; it’s possible you have a rear main seal leak.

Conclusion

So, Crankcase oil additives can sometimes help slow a leak; by causing aged gaskets and seals to swell; but no additive will stop a major leak or repair a broken gasket or worn seal. Sooner or later you will have to replace the leaky gasket or seal.

Finally, Valve cover gaskets are usually easy to replace; but intake manifold gaskets; pan gaskets and crankshaft seals are much more difficult.

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