Rear main seal leaks tend to worsen when an engine has warmed to its standard operating procedure. The following are the most common signs of a rear main seal leak. Being mindful of such symptoms will assist you in coming to an early diagnosis, thereby expediting the repair process. Signs of a Leaking Rear Main SealĪ rear main seal leak can be identified in a number of ways, some of which prove far more evident than others.

As such, a noticeable leak is presented, which can range in severity by substantial margins. Without a properly functioning rear main seal, a vehicle’s engine oil is allowed to escape outside of its normal point of retention within the crankcase. In most cases, it is impossible to view an engine’s rear main seal, once it has been installed, and a vehicle has been returned to service. Seals of this type are typically driven into a recess within an engine’s rear cover and are generally concealed within the bell-housing of the transmission itself. This, in turn, gives birth to the rear main seal’s nickname as the rear crankshaft seal. In the simplest of terms, a rear main seal is a seal used to prevent oil loss from the rear of an engine, where the engine’s crankshaft mounts to the transmission, via a flywheel or flexplate.

Will Thicker Oil Help a Rear Main Seal Leak?.

Can a Rear Main Seal Be Replaced Without Removing the Transmission?.What Causes the Seal to Leak or Go Bad?.#3 – Oil Saturation of Vehicle Underbody.

2001 5.9 cummins rear main seal