How bad is a rear main seal leak? Really bad. The major danger is that it can possibly lower your engine oil level a significant amount very quickly which can cause catastrophic engine damage. Unlike a valve cover gasket leak or another engine oil leak higher up on your engine, a rear main seal leak doesn’t smoke or really give an indication that it’s leaking. Also, a rear main seal leak won’t leak while your engine is off. So while you may see a couple of drips on your driveway or in your parking spot, those drips aren’t a good indication of how much oil is actually leaking out of your engine while you are driving.
How Can You Tell if You Have a Rear Main Seal Leak?
- Engine oil dripping from your transmission bell housing
- Engine oil on the back of your flywheel or flexplate
- Engine oil dripping from the back of your oil pan
Engine Oil Dripping from Your Transmission Bell Housing
The rear main seal in your engine is right at the back of the engine sealing your crankshaft where it exits the engine. If you’ve got an oil leak at that seal, the oil will drip down the back of your engine. The back of your engine is bolted to your bell housing, which is the front of your transmission. If you’ve got a rear main seal leak, the oil will drip down into the bell housing and will drip through somewhere in that area. This often will result in drops of oil on the bottom of your bell housing. Be careful though. A leak from higher up in your engine, from the back of your valve cover gasket, or even the back of your oil pan can also cause oil to drip off the bottom of your bell housing, so make sure to check for other oil leaks before you jump to any conclusions.
Engine Oil on the Back of Your Flywheel or Flexplate
As we mentioned, higher oil leaks can still leave traces of oil around the back of your engine. One of the best ways to prove that your oil leak is actually a rear main seal leak is to check for oil on the engine side of your flywheel or flexplate. Most transmissions will have an inspection cover on the bell housing that you can remove to peek in and check things out. Open that cover and grab a flashlight and see if you can find evidence of a rear main seal leak. If it’s dry inside the transmission bell housing, you probably have a leak elsewhere.
Engine Oil Dripping from the Back of Your Oil Pan
Like having oil on your bell housing, the back of your oil pan can get oil if you’ve got a rear main seal leak. Make sure to check again for other indications of a rear main seal leak as oil can drip here if your oil pan drain bolt is loose, or if you’ve got an oil pan gasket leak.
If you’re wondering why you’ve got a rear main seal leak, join us in the garage to understand more about how the seal works and why it might start leaking on your car! If you’ve got other things wrong with your car, such as engine ticking or a bad wheel bearing, join me for some other great tips on keeping your car running quietly, safely, and leak free!
pictures provided by:
rear_main_seal_leak.jpg – by LoveTheWInd – Licensed by Getty Images – Original Link