by bigBADbenny » Wed Feb 14, 2024 6:30 am
It’s a common issue, generally known as the *rear main seal*.
There’s no Band-Aid solution, just get it done by a mechanic experienced in Subarus.
Correct installation of the rear main seal requires a specific Service Tool to set the specific insertion depth of the seal, or observation of that consideration if using conventional methods.
The procedure of course is in the FSM factory service manual, using the service tool, oem or aftermarket, eg company23 etc.
Use only OEM genuine gasket and prepare the area carefully.
Insert it too far and it will leak oil and or block internal passages, not enough and it might potentially fail prematurely.
I prefer to think of bigger jobs as opportunities for other maintenance and upgrades.
That’s eg resealing the rear AOS plate, replacing reverse and or neutral position switches, inspect CV boots, upgrade gearbox engine & pitch stop mounts, inspect flex plate or replace/upgrade clutch, etc.
I’m gen4 GT so I went with a DCCD 6mt, exedy HD clutch and lightweight flywheel, but next time (very soon lol) I’m going back to a stock flywheel, stock clutch, as for me, those “upgrades” simply aren’t required for my mods and driving requirements.
If you have engine oil further up the bell housing area, above the rear main seal, check the two block pcv breathers (ej20x/y & 255) : if the hoses there (centre breather & pcv sump stack tube) are cracked, you’ll find leaking oil on the top rear of the block and persistent negative fuel trims.
A leaking turbo oil drain is more likely to drip oil onto the crossmember and driveshaft area, but is still a consideration.
A blown rhs inner cv boot will create a mess in the area but the grease is heavier and has a distinct smell to it.
Essentially just go with a mechanic who has experience with this job, who will warranty the work. Discuss these considerations with them prior, get quotes. It’s likely to cost you less in the long term.