RMS Fail Club
Senior Member
Joined: Dec 2025
Posts: 373
Likes: 36
From: Keep it simple - keep it OEM
AMG C63s Coupe
The spring-and-plunger component is a pressure control device that regulates pressure on the crankcase side of the OVS. BMW and VAG/Porsche use a polymer membrane in this location. Remember, all German automotive engineers went to a small number of universities, consult with the same small number of specialists (FEV and AVL), and go to the same small number of technical conferences. The engineering gene pool is shallow and there is nothing new under the sun.
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we ( i) dont know for 100% what is the cause but it “look like” its this valve as showen in dissection video.
if its this valve then check why its stuck.
allways do a step down …
mayby plastic engeneer guy did a mistake or somewhat else ?
we need a close up picture from this part.
such a valve is no rocket technology.
it looks like there is a cause more with LS2 too.
specialists FEV / AVL ??? Whats means this ?
Last edited by C63s_Jack; Mar 26, 2026 at 04:21 AM.
Out Of Control!!
Joined: Sep 2018
Posts: 14,644
Likes: 4,551
From: unbegrenzt
2017 GLE350 4MATIC
Read about FEV and AVL. Also read about ika. Easy to find large volumes of information on the interwebs.
This video states 6 check valves per OVS, therefore 12 check valves per engine. As expected. Watch the video from 4:42.
These parts from MB are pure garbage in basic design and are undersized, adding insult to injury. MB performing to expectation as usual.
This video states 6 check valves per OVS, therefore 12 check valves per engine. As expected. Watch the video from 4:42.
These parts from MB are pure garbage in basic design and are undersized, adding insult to injury. MB performing to expectation as usual.
Junior Member
Joined: Apr 2016
Posts: 71
Likes: 32
2020 AMG GLC63
Fidelity, like all warranty coverage will only pay per repair as they fail, I have seen codes thrown for the OVS while in for RMS and they're covered at the same time, but it can't be a "while we are in there" for RMS.
Also, NY dealer labor hours, part costs, and per hour labor rates billed are just crazy sometimes. I'd suggest customers go visit Chris at Benzel Busch Mercedes-Benz in Englewood, New Jersey.
Trenton O. Gibson
tgibson@highline-autos.com
Highline Autos
Direct: 602.909.9216
Office: 480.348.0777
Also, NY dealer labor hours, part costs, and per hour labor rates billed are just crazy sometimes. I'd suggest customers go visit Chris at Benzel Busch Mercedes-Benz in Englewood, New Jersey.
Trenton O. Gibson
tgibson@highline-autos.com
Highline Autos
Direct: 602.909.9216
Office: 480.348.0777
Oil separators clogged, caused a leak, needed to get RMS replaced as well. Fidelity said they'd cover it. The Mercedes dealer was requesting an insane amount of hours to complete the job and Fidelity rejected it. I asked MB to release the car so I could take it to my trusted indy and the Mercedes dealer eventually revised their plan to fall in line with Fidelity. It was a total cash grab attempt.
SPONSOR
Joined: Apr 2021
Posts: 1,544
Likes: 466
From: Scottsdale, Arizona
2001 E55AMG
I just battled this.
Oil separators clogged, caused a leak, needed to get RMS replaced as well. Fidelity said they'd cover it. The Mercedes dealer was requesting an insane amount of hours to complete the job and Fidelity rejected it. I asked MB to release the car so I could take it to my trusted indy and the Mercedes dealer eventually revised their plan to fall in line with Fidelity. It was a total cash grab attempt.
Oil separators clogged, caused a leak, needed to get RMS replaced as well. Fidelity said they'd cover it. The Mercedes dealer was requesting an insane amount of hours to complete the job and Fidelity rejected it. I asked MB to release the car so I could take it to my trusted indy and the Mercedes dealer eventually revised their plan to fall in line with Fidelity. It was a total cash grab attempt.
Trenton O. Gibson
tgibson@highline-autos.com
Highline Autos
Direct: 602.909.9216
Office: 480.348.0777
MBWorld Fanatic!
Joined: Aug 2007
Posts: 1,793
Likes: 784
From: Pacific Northwest
2001 S600 V12 Sold, 2011 Jaguar XFR Sold, 2017 S550 4-Matic, 2018 S63 AMG Sedan
I just battled this.
Oil separators clogged, caused a leak, needed to get RMS replaced as well. Fidelity said they'd cover it. The Mercedes dealer was requesting an insane amount of hours to complete the job and Fidelity rejected it. I asked MB to release the car so I could take it to my trusted indy and the Mercedes dealer eventually revised their plan to fall in line with Fidelity. It was a total cash grab attempt.
Oil separators clogged, caused a leak, needed to get RMS replaced as well. Fidelity said they'd cover it. The Mercedes dealer was requesting an insane amount of hours to complete the job and Fidelity rejected it. I asked MB to release the car so I could take it to my trusted indy and the Mercedes dealer eventually revised their plan to fall in line with Fidelity. It was a total cash grab attempt.
Welcome to the RMS Fail Club. If you're here, you're likely not having a good day
If you had a failed RMS, cut and paste the following and post your pertinent details to add to the database of affected vehicles:
Year: 2019
Model: E63S
RMS Failure Mileage: 38K miles
Style/Frequency of Driving: weekend/spirited
Original Owner: No
Failed Before or After Warranty: After
Has it re-leaked after repair: no
Cost to repair: $5700 (warranty vs OOP)
Who repaired it: Indy vs dealership
Junior Member
Joined: Apr 2016
Posts: 71
Likes: 32
2020 AMG GLC63
Did you post the detils bout your c\RMS failure in this thread?
Welcome to the RMS Fail Club. If you're here, you're likely not having a good day
If you had a failed RMS, cut and paste the following and post your pertinent details to add to the database of affected vehicles:
Year: 2019
Model: E63S
RMS Failure Mileage: 38K miles
Style/Frequency of Driving: weekend/spirited
Original Owner: No
Failed Before or After Warranty: After
Has it re-leaked after repair: no
Cost to repair: $5700 (warranty vs OOP)
Who repaired it: Indy vs dealership
Welcome to the RMS Fail Club. If you're here, you're likely not having a good day
If you had a failed RMS, cut and paste the following and post your pertinent details to add to the database of affected vehicles:
Year: 2019
Model: E63S
RMS Failure Mileage: 38K miles
Style/Frequency of Driving: weekend/spirited
Original Owner: No
Failed Before or After Warranty: After
Has it re-leaked after repair: no
Cost to repair: $5700 (warranty vs OOP)
Who repaired it: Indy vs dealership
Year: 2020
Model: GLC63
RMS Failure Mileage: 40,109 miles
Style/Frequency of Driving: Daily driver, 4 seasons commute to work
Original Owner: No
Failed Before or After Warranty: After factory warranty, but covered by Fidelity extended warranty
Has it re-leaked after repair: No
Cost to repair: $250 out of pocket, $16,233 by warranty (they also changed the valve cover gaskets as that's now standard procedure from Mercedes)
Who repaired it: Mercedes-Benz dealership
Last edited by Prago; Apr 10, 2026 at 10:56 AM.
Junior Member
Joined: Sep 2025
Posts: 32
Likes: 20
From: Peachtree City GA
2019 E63S Wagon
8k miles and 4.5 months after OVS replacement...
The service bulletin was issued July 16, 2025 says to do the OVS replacement, then see ift he RMS continues to leak. If no leak send the car on its merry way. Just found this post today, but probably why they didn't do the RMS replacement on your car. How are things going since the repair???
https://static.nhtsa.gov/odi/tsbs/20...20807-0001.pdf
https://static.nhtsa.gov/odi/tsbs/20...20807-0001.pdf
my experience was that they need to see an "active" leak to warrant replacing the RMS. the shop that replaced my oil-vapor separators cleaned it all up and took photos of the cleaned area. i'm going to have them inspect it again when go in for routine service, and if there is evidence of a leak since they replaced the OVS, then they should be able to get repair authorization to replace the RMS.
however, this particular TSB just appears to be related to excess oil consumption or the smell of burning oil or the visible traces of an oil leak.
"Customer complains of oil use, oil leaking or oil smell."
however, this particular TSB just appears to be related to excess oil consumption or the smell of burning oil or the visible traces of an oil leak.
"Customer complains of oil use, oil leaking or oil smell."
