2018 W213 E63S Sedan - 41k miles, rear main seal seal/retainer failure
active leak of engine oil when the car is sitting
happened 2 days after i brought it to an aftermarket shop for some tires and an alignment (did they beat on it? idk) and 1 day after installing blackboost cold air intake. coincientdal? who knows
could it be "blow by" from running lots of boost on a tune (oil leaking out of rings/ring seal)? doubt it
could i have blocked/messaged with crankcase ventilation when doing the intakes? not sure
either way, tranny gotta come out...
looked on the w213 threads to see if anybody else had this issue, figured i get it started. couple of tech friends of mine have said it's fairly common. google says w211 had it a lot. w212 not sure.
idk why taking out a part that failed and putting in the exact same part is going to fix the issue but hey... we'll see
active leak of engine oil when the car is sitting
happened 2 days after i brought it to an aftermarket shop for some tires and an alignment (did they beat on it? idk) and 1 day after installing blackboost cold air intake. coincientdal? who knows
could it be "blow by" from running lots of boost on a tune (oil leaking out of rings/ring seal)? doubt it
could i have blocked/messaged with crankcase ventilation when doing the intakes? not sure
either way, tranny gotta come out...
looked on the w213 threads to see if anybody else had this issue, figured i get it started. couple of tech friends of mine have said it's fairly common. google says w211 had it a lot. w212 not sure.
idk why taking out a part that failed and putting in the exact same part is going to fix the issue but hey... we'll see
Sounds to me your engine was not all that healthy with that tune, to begin with. That could have caused some oil-related failures you are seeing now (knock, blowby, etc etc)
Either way, that's terrible to read, I would start with logging (after the repairs) to see what your engine is doing
Last edited by kponti; Oct 15, 2021 at 01:01 PM.




active leak of engine oil when the car is sitting
happened 2 days after i brought it to an aftermarket shop for some tires and an alignment (did they beat on it? idk) and 1 day after installing blackboost cold air intake. coincientdal? who knows
could it be "blow by" from running lots of boost on a tune (oil leaking out of rings/ring seal)? doubt it
could i have blocked/messaged with crankcase ventilation when doing the intakes? not sure
either way, tranny gotta come out...
looked on the w213 threads to see if anybody else had this issue, figured i get it started. couple of tech friends of mine have said it's fairly common. google says w211 had it a lot. w212 not sure.
idk why taking out a part that failed and putting in the exact same part is going to fix the issue but hey... we'll see
LMAO @ She's leakin; She's soakin wet... Now you have the Ying Yang Twinz song in my head..
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All in all, things are looking positive. I’ve heard the 4 oil separators (2 left, 2 right) are at play here.
I have it on good account that if you replace the rear main seal and the oil separators (as advised by Mercedes Support under one car's support case, not mine), the problem went away.
I have heard of a case exactly like yours. Rear main seal failed, replace it (and not the oil separators), failed again. I think I was told that process repeated 3-4x times before they finally went to support and were told oil separators.
i got no DTCs/CELs so i guess i caught it early




i wanted an f90 m5 but i like to run a stage 2 tune and with that engine, it just can’t reliably handle torque due to weak rods/rod bearing design from what i can tell
and a 2021 w213 is $2,200/mo anyway you spin it, i just didn’t see the value




i wanted an f90 m5 but i like to run a stage 2 tune and with that engine, it just can’t reliably handle torque due to weak rods/rod bearing design from what i can tell
and a 2021 w213 is $2,200/mo anyway you spin it, i just didn’t see the value




It's in the shop today for an oil change and I asked them to chase the leak. So far, they are suspecting RMS but cleaned it up underneath and will test drive to see if they can pinpoint the leak exactly.
It's in the shop today for an oil change and I asked them to chase the leak. So far, they are suspecting RMS but cleaned it up underneath and will test drive to see if they can pinpoint the leak exactly.







