2018 Mercedes-Benz C 300 problems & reliability
99 owner complaints filed with NHTSA for the 2018 Mercedes-Benz C 300, alongside 18 safety recall campaigns. Last verified Sep 21, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several components.
1 complaint report injuries (1 injured).
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Engine → | 34 | 34% |
| Unknown / Other | 20 | 20% |
| Structure → | 14 | 14% |
| Steering → | 12 | 12% |
| Electrical System → | 10 | 10% |
| Fuel/propulsion System | 9 | 9% |
| Air Bags | 4 | 4% |
| Forward Collision Avoidance | 4 | 4% |
| Communication | 3 | 3% |
| Visibility | 3 | 3% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 22 reported components →Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Complaints by incident year
What owners report
“The contact owns a 2018 Mercedes-Benz C-300. The contact stated that while driving 70 MPH South on the interstate towards Miami, the front panel detached without warning. The contact pulled over to inspect the vehicle and became aware that the panel between the windshield and sunroof had detached. The contact stated…”
Structure · filed Aug 26, 2026
“Transmission failed, yes available for inspection Very bad safety issue Yes it has been confirmed by dealship Yes by the deanship Yes there was warning lamps that appeared in January 2026”
Unknown / Other · filed Jun 16, 2026
“The contact's wife owns a 2018 Mercedes-Benz C300. The contact stated that while washing the vehicle, a part of the panoramic roof started moving while depressing the glass. The contact stated that there was water leaking into the vehicle from the glass. Upon investigation, the contact discovered NHTSA Campaign…”
Structure · filed Mar 5, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Federal defect investigations
- Desiccated Air Bag Inflator Rupture
Engineering Analysis EA21002 · opened Sep 17, 2021 · open
Technical service bulletins
183 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2018 Mercedes-Benz C 300. The 10 most recent:
Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering…
LI46.35-P-067339 · Service Bulletin/Repair Instructions · issued Aug 28, 2026
Complaint • Harsh 1‑2, 2‑3, and/or 3‑4 shift • Jerky shifting • Jolting when accelerating from stop Cause Insufficient software application causing elevated K81/K27/B05 fill time adaptations and elevated torque…
LI27.60-P-076554 · Service Bulletin/Repair Instructions · issued Aug 26, 2026
Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th…
LI72.20-P-075746 · Service Bulletin/Repair Instructions · issued Aug 24, 2026
Dear Mercedes-Benz Owner: In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA is extending the warranty coverage for…
CL - Tank Leak Detection · Warranty Program/Extension · issued Aug 15, 2026
Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause…
LI54.65-P-080132 · Service Bulletin/Repair Instructions · issued Aug 12, 2026
Complaint A popup is seen on the HU with the message "data connection temporarily not available". Potentially affected functionalities in NTG4.5, NTG5 1.Weather 2.Local Search 3.IP Radio 4.Send2Car 5.Speech Detection…
LI82.85-P-079087 · Service Bulletin/Repair Instructions · issued Aug 6, 2026
Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim…
LI82.62-P-078631 · Service Bulletin/Repair Instructions · issued Aug 6, 2026
Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case is necessary, all supporting documentation is available. This should not be…
LI27.00-P-075630 · Service Bulletin/Repair Instructions · issued Aug 5, 2026
Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global supply constraint. 236.17 ATF 1L and 5L (PNs: A002989060312 and A002989060313)…
LI27.00-P-080840 · Service Bulletin/Repair Instructions · issued Aug 4, 2026
This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below. In our continuing efforts to ensure the proper performance of Mercedes-Benz…
EW - DMTL · Warranty Program/Extension · issued Jul 31, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2018 Mercedes-Benz C 300 has 18 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2018 Mercedes-Benz C 300?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.