Mercedes-Benz bulletin LI01.20-P-080884
What it saysComplaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Remedy If oil leaks are found at left or right cylinder head cover area please… NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service bulletin dated Aug 12, 2026, received Aug 18, 2026, about the engine. It names 74 model years (2016–2026). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationComplaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Remedy If oil leaks are found at left or right cylinder head cover area please collect the following information and open TIPS case. 1. Collect photos of the leak 2. Include close up and wide view photos to accurately represent the location 3. Include if the vehicle has a "check oil level" Light on in the cluster or fault codes 4. Check oil level as per WIS to verify level and calculate possible oil loss from the leak 5. Identify and communicate the severity of the leak and provide supporting documentation 6. Open a TIPS case with the above information and submit to the Powertrain team for processing
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| LI01.20-P-080884 | Service bulletin | Aug 12, 2026 | 11036229 | PDF, 35 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themand 23 more on this site: 2020 Mercedes-Benz GLE-Class, 2026 Mercedes-Benz GLS-Class, 2025 Mercedes-Benz GLS-Class, 2024 Mercedes-Benz GLS-Class, 2023 Mercedes-Benz GLS-Class, 2022 Mercedes-Benz GLS-Class, 2021 Mercedes-Benz GLS-Class, 2020 Mercedes-Benz GLS-Class, 2026 Mercedes-Benz S-Class, 2025 Mercedes-Benz S-Class, 2024 Mercedes-Benz S-Class, 2023 Mercedes-Benz S-Class, 2022 Mercedes-Benz S-Class, 2021 Mercedes-Benz S-Class, 2020 Mercedes-Benz S-Class, 2019 Mercedes-Benz S-Class, 2018 Mercedes-Benz S-Class, 2017 Mercedes-Benz S-Class, 2026 Mercedes-Benz SL-Class, 2025 Mercedes-Benz SL-Class, 2024 Mercedes-Benz SL-Class, 2023 Mercedes-Benz SL-Class, 2022 Mercedes-Benz SL-Class.
Also filed against model years this site has no page for: 2022 Mercedes-Benz AMG C63 S; 2022 Mercedes-Benz AMG E63S; 2022 Mercedes-Benz AMG GT63; 2022 Mercedes-Benz AMG GT63 S; 2024 Mercedes-Benz AMG GT63 S E; 2024 Mercedes-Benz AMG GT63 S E Performance; 2026 Mercedes-Benz AMG GT63 S E Performance 4MATIC+; 2023 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG S 63 E 4MATIC+; 2026 Mercedes-Benz AMG S 63 E 4MATIC+; 2024 Mercedes-Benz AMG SL63 S E.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 63 model years this bulletin names have filed 2,329 complaints with NHTSA since 2015. 633 of them name Engine — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2017 Mercedes-Benz C-Class, the 12 owners who gave an odometer reading for Engine reported it at a median of 36,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
My 2017 G550 misfired on a highway and I had total failure with kids in the backseat creating an immediate life-safety hazard. This issue was caused by the M176 engine, which is known to create misfires. Mercedes tried to blame it on me not changing my spark plus, but I showed proof they were changed with a certified Mercedes mechanic.
2017 Mercedes-Benz G-Class · Engine · filed with NHTSA Oct 27, 2026 · ODI 11773912
I brought my car in for routine service and was told I needed a rear main seal. I had the car inspected when I purchased it appx 13k miles ago because I saw online there was a lot of people having this issue with their vehicles. It’s a known manufacturer defect. At that time there was no issue. Now at 40k miles it began to leak.
2019 Mercedes-Benz E-Class · Engine · filed with NHTSA Jan 4, 2026 · ODI 11708627
On July 7, 2026, my 2022 Mercedes-Benz GLE 350 experienced a serious engine malfunction. After stopping at a traffic light, the engine began shaking violently and idling roughly. When the traffic light turned green, the vehicle accelerated extremely slowly and had very little power, making it difficult to clear the intersection.
2022 Mercedes-Benz GLE-Class · Engine · filed with NHTSA Jul 13, 2026 · ODI 11749953
In depth: 2017 Mercedes-Benz C-Class engine problems → · 2016 Mercedes-Benz C-Class engine problems →
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the engine
Source: same model, same component group84 other manufacturer communications filed against these Mercedes-Benz models under the same component group (engine), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI18.00-P-073137 | Service bulletin | Sep 26, 2026 | Complaint Sporadic warning message in instrument cluster "Engine oil pressure stop switch off vehicle" (or similar) is shown in red on vehi… |
| LI20.10-P-075374 | Service bulletin | Sep 17, 2026 | Complaint Red coolant warning in instrument cluster. Fault codes U019F00 or U019F87 current/stored in MRG1 control unit. Cause Various cause… |
| PSL-NCU Return Parts 8/14 | Other | Aug 15, 2026 | Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be ret… |
| LI07.10-P-080384 | Service bulletin | Aug 7, 2026 | Complaint Customer reports Check Engine Light with possible loss of power concern. The Following DTC's are present • P210185 - The throttle… |
| NCU - 2026010004 | Service campaign | Jul 27, 2026 | • Always use the latest XENTRY Diagnosis software release with all available add-ons. • Make sure to follow the operation steps exactly as d… |
| LI20.10-P-072886 | Service bulletin | Jul 24, 2026 | Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME… |
| Emissions - 2024100016 | Emissions | Jul 24, 2026 | Mercedes-Benz AG (“MBAG”), the manufacturer of Mercedes-Benz, has determined that on certain MY 2019-2021 C-Class, G-Class, GLC, GT, S-Class… |
| LI07.61-P-080241 | Service bulletin | Jun 11, 2026 | Complaint CEL ON with DTC P061197 "the control unit fuel injector has a malfunction output stage fault of control unit is restricted" active… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mercedes-Benz, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mercedes-Benz LI01.20-P-080884 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the LI01.20-P-080884 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Mercedes-Benz warranty extension on file lists the ones Mercedes-Benz has filed.
Which vehicles does LI01.20-P-080884 cover?
The manufacturer filed it against 74 model years: 2026 Mercedes-Benz AMG GT, 2025 Mercedes-Benz AMG GT, 2024 Mercedes-Benz AMG GT, 2023 Mercedes-Benz AMG GT, 2021 Mercedes-Benz AMG GT, 2020 Mercedes-Benz AMG GT and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.