VERY EXPENSIVE Oil Seperator Failure
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Member
Joined: Apr 2012
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From: southern California
'21 AMG GLE63S, '17 BMW 340iGT
VERY EXPENSIVE Oil Seperator Failure
Watch-out for this! The oil separator is some sort of over-fancy PCV valve. It is in the valley. My 2021 AMG GLE 63S in at the dealership now because it failed. That caused the rear main seal to fail, and the motor - alternator for the mild hybrid system was drenched in oil, so is also being replaced. The dealership told me today that the motor - alternator is very expensive. They removed the engine and front suspension to do the repair. I found a video stating that the thermostats are also failure-prone, so am having them replace it (the part also is about $750). Fortunately, I bought the 100,000 mile warranty, and it had about 2,300 miles left on it, so my cost will only be for the thermostat failure. Buying this thing was a mistake. Mercedes-Benz needs to get back to making top-quality vehicles.
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Watch-out for this! The oil separator is some sort of over-fancy PCV valve. It is in the valley. My 2021 AMG GLE 63S in at the dealership now because it failed. That caused the rear main seal to fail, and the motor - alternator for the mild hybrid system was drenched in oil, so is also being replaced. The dealership told me today that the motor - alternator is very expensive. They removed the engine and front suspension to do the repair. I found a video stating that the thermostats are also failure-prone, so am having them replace it (the part also is about $750). Fortunately, I bought the 100,000 mile warranty, and it had about 2,300 miles left on it, so my cost will only be for the thermostat failure. Buying this thing was a mistake. Mercedes-Benz needs to get back to making top-quality vehicles.
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Joined: Jun 2004
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2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
Thanks for thinking of the thread @W205C43PFL
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
Last edited by PeterUbers; Jul 9, 2025 at 12:59 PM.
MBWorld God!
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Thanks for thinking of the thread @W205C43PFL
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
Joined: Apr 2006
Posts: 560
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From: LHC, Arizona
2024 GLE 63 S Coupe 2020 E 63 S
I've been holding onto my m157 2019 GLE 63s coupe because I don't want the hybrid system. Also bought a 2020 E63s because it is seeming the last amg without a hybrid. The alternator motor are pricey
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2021 GLE 63S / 1991 560 SEL / 1994 SL600 /DD 2010 C300 6Spd Manual
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Thread Starter
Member
Joined: Apr 2012
Posts: 97
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From: southern California
'21 AMG GLE63S, '17 BMW 340iGT
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Do you mind telling us what fuel you use, oil change intervals, type of oil viscosity and weight used, brand, type of oil filter used, humditiy level on average, temperature on average, short or long trips often (I assume is the latter given the mileage), track or street use mainly highway? Do you tow, usually full cargo or only you and a passenger, etc. All will be good information as a data point.
Thread Starter
Member
Joined: Apr 2012
Posts: 97
Likes: 19
From: southern California
'21 AMG GLE63S, '17 BMW 340iGT
Do you mind telling us what fuel you use, oil change intervals, type of oil viscosity and weight used, brand, type of oil filter used, humditiy level on average, temperature on average, short or long trips often (I assume is the latter given the mileage), track or street use mainly highway? Do you tow, usually full cargo or only you and a passenger, etc. All will be good information as a data point.
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Joined: Dec 2021
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From: United States
GL550 / AMG GTS
Thanks for thinking of the thread @W205C43PFL
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
OP - add your car to this database please
RMS Fail Database m17X engines
Also see NUMEROUS threads in this sticky discussing the RMS issue beyond what you've described:
https://mbworld.org/forums/w213-amg/...fixes-diy.html
MBWorld God!
Joined: Dec 2019
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None of those things are the problem. It is a too-cheap part in an expensive vehicle. Maybe they saved a Euro or two on it????? In my case, it has been mostly used for easy highway driving, never towing, racing, Etc., and it has always had top-quality oil to M-B specifications at recommended change intervals.
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Joined: Dec 2015
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From: Suburban Maryland
2023 E 450 Sedan. 2018 GLC 300. 2013 E 350 Coupe (retired)
Does anyone know if this type of repair would be covered under the more limited cpo warranty? I imagine they would squirm out of replacing the mounts for free, arguing those are 'wear items'.
Thread Starter
Member
Joined: Apr 2012
Posts: 97
Likes: 19
From: southern California
'21 AMG GLE63S, '17 BMW 340iGT
This vehicle had already spent too much time at that dealership, as the 48-volt battery failed twice. I got a nail in a tire when it was new, and found that the lug bolt covers were defective, so it had to be serviced for that after parts came from Germany. The most recent change of the 48-volt battery, they messed-up some back seat wiring so the folding did not work, so it had to go back for that. It also had a grabby center differential, fixed with replacement of the oil.
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They tried to argue they were wear items, but I pointed-out that many cars with 200,000 miles on them still have the original motor mounts, and told them I'd be happy to speak with the District about it. That is about the last thing they want, and a good service guy got them covered.
This vehicle had already spent too much time at that dealership, as the 48-volt battery failed twice. I got a nail in a tire when it was new, and found that the lug bolt covers were defective, so it had to be serviced for that after parts came from Germany. The most recent change of the 48-volt battery, they messed-up some back seat wiring so the folding did not work, so it had to go back for that. It also had a grabby center differential, fixed with replacement of the oil.
This vehicle had already spent too much time at that dealership, as the 48-volt battery failed twice. I got a nail in a tire when it was new, and found that the lug bolt covers were defective, so it had to be serviced for that after parts came from Germany. The most recent change of the 48-volt battery, they messed-up some back seat wiring so the folding did not work, so it had to go back for that. It also had a grabby center differential, fixed with replacement of the oil.
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Joined: Dec 2019
Posts: 32,222
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Last edited by W205C43PFL; Jul 13, 2025 at 07:47 AM.
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2018 Amg E63s Edition 1
Sorry! Been There!
Watch-out for this! The oil separator is some sort of over-fancy PCV valve. It is in the valley. My 2021 AMG GLE 63S in at the dealership now because it failed. That caused the rear main seal to fail, and the motor - alternator for the mild hybrid system was drenched in oil, so is also being replaced. The dealership told me today that the motor - alternator is very expensive. They removed the engine and front suspension to do the repair. I found a video stating that the thermostats are also failure-prone, so am having them replace it (the part also is about $750). Fortunately, I bought the 100,000 mile warranty, and it had about 2,300 miles left on it, so my cost will only be for the thermostat failure. Buying this thing was a mistake. Mercedes-Benz needs to get back to making top-quality vehicles.
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Joined: Sep 2009
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2021 GLE 63S / 1991 560 SEL / 1994 SL600 /DD 2010 C300 6Spd Manual
Its the sleeping giant in every M177 engine. That's a lot of AMG models, including my E63s. It cost me $8k at an independent shop. Took nearly 30 hours, the parts were a few hundred. MB should have recalled. Mb wouldn't even work on it. The Oil separator is a useless emissions part to attempt to save microscopic oil droplets from going out the exhaust. Its part of the Crack case PCV system and it has this little plastic ball valve that gets gummed up and stuck over time. Mine went at 47k miles!!!! If you read these forums you'll see some going at 10k and 20k miles! Mb redesigned the RMS and its much sturdier, but no redesign on the oil separator. AOS, as its called, is a set of plastic hoses that snake from the back of the engine to the front. There is no way to clean them or inspect them without massive labor hours. Another solution would be to replace with an oil catch can, however none exist and the space is very tight for something like that. If you have one of these cars, I would drive it easy and go sell it. Im keeping mine now that I've paid and am on the other side. But, eventually I will sell, maybe a year from now. I dont trust the car. Its a 2018 edition 1. I've had to replace the rear suspension as well for $6k. Fast and amazing handling, but I dont trust the quality.
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From: unbegrenzt
2017 GLE350 4MATIC
