2018 Mercedes-Benz C-Class
Problems, recalls and owner-reported issues
Engine is the leading concern among 130 owner complaints filed for this model year. This is the 15th highest complaint count among 23 C-Class model years with reports.
Of the 2018 reports, 5 involved a crash. 2 people were injured.
What owners report most often
Recalls and investigations
No safety recalls on file.
Representative owner complaints: structure
19 reports, newest first. Show all
Structure, Sep 16, 2026
Front roof panel came detached at hwy speed
Structure, Aug 26, 2026
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 that water started entering the vehicle from several areas. The sunroof was inoperable. The contact called the insurance company. The contact associated the failure with NHTSA Campaign Number: 23V854000 (Structure). The local dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted, but no additional assistance was provided. The approximate failure mileage was 83,000.
Structure, Visibility/wiper, Jul 30, 2026
I have begun noticing symptoms of the adhesive failing, such as excessive wind noise coming from the front roof area and visible gaps/separation between the panel and the vehicle body. This poses a severe safety risk, as the panel could completely detach while driving and become a high-speed road hazard. No warning lights have appeared. The vehicle and component are available for inspection upon request.
Suspension, Structure, Other or unspecified, Jul 24, 2026
2018 Mercedes C300 - a hole rusted through the rear subframe causing structural safety concerns. This car has been routinely washed weekly and the frame should not have rusted through within only 8 years. This also led to a large repair bill.
Structure, Jun 10, 2026
****Please force Merces to recall all VIN's!******* NHTSA ID Number: 23V854000 1) Front glass roof panel came off while driving the car on the freeway. I didn't see or hear anything. When I got out of the car, I saw the entire piece has come off. This has caused my sunroof to malfunction, and it won't close now. I garage my car and barely drive it. I bought it used in Dec. 2021. There was about 46,000 on it in Dec 2021 and now (June 2026) the mileage is 51,000. Yes, the car is available for inspection. 2) I was on the freeway, didn't see it come off. No cars immediately in front or behind me. 3) There have been many complaints that this has happened, but Mercedes won't fix it and just say our VIN's are not part of the recall. Mercedes has not taken responsibility that this has affected more cars than they are admitting to. Mercedes says my VIN is not on their list too. 2018 Mercedes C 300 4Matic Sedan- 4) I will take to a Mercedes Dealership to get an estimate soon. 5) No warning lights or sounds.
Structure, May 22, 2026
Mercedes-benz usa. llc (mbusa) is recalling certain 2014-2020 c-class, cla, gla, s-class. glc, and gle vehicles. please refer to mbusa's recall report for specific vehicle details. the front roof panel located between the windshield and the panoramic sunroof may not have been bonded correctly to the vehicle during a prior repair, allowing the front panel to detach from the vehicle., Consequence A detached roof panel can become a roao hazard, increasing the risk of a crash I went to the dealership about this complaint 2 years ago not even knowing about an official recall of this exact problem. I don't drive my car as much because it was an issue that never got fixed. I was never told about a recall. They said there is a whistling and it could fly off (the panel)
Structure, Mar 5, 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 Number: 23V854000 (Structure); however, the VIN was not included in the recall. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was filed. The manufacturer confirmed that the VIN was not included in the recall. The contact was then referred to the NHTSA Hotline to report the failure. The failure mileage was unknown.
Structure, Aug 19, 2025
The contact owns a 2018 Mercedes-Benz C300. The contact stated that while driving approximately 60 MPH, a part of the panoramic roof towards the driver's side detached from the vehicle. The contact pulled over to inspect the vehicle. The part was no longer attached, and the contact had to continue driving. The failure caused additional electrical failures due to water entering the cabin of the vehicle. The contact stated that the sunroof failed to open, and the infotainment center was inoperable. The contact found information on NHTSA Campaign Number: 23V854000 (Structure); however, the VIN was not included. The vehicle was taken to the dealer, who related the failure to the recall; however, the vehicle could not be repaired under the recall because the VIN was not available. The vehicle was not repaired. The manufacturer was informed of the failure and opened a case. The manufacturer confirmed that the VIN was not included in the recall. The manufacturer referred the contact to the NHTSA Hotline to file a complaint. The failure mileage was approximately 109,000.
Structure, Jun 4, 2025
The contact owns a 2018 Mercedes-Benz C300. The contact stated that after washing the vehicle, the contact became aware that the adhesive attaching the rear window to the convertible top had started to detach. Upon further inspection, the contact became aware that water had seeped into the vehicle through the crack. There was no warning light illuminated. The local dealer was contacted; however, the vehicle was not diagnosed. The contact was also informed that the VIN was not under recall. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 49,000.
Structure, Sep 12, 2024
Problem a recall was done on certain Mercedes vehicles where the front panel of the roof between the panoramic sunroof and windshield has defects in gluing or bonding agent from the manufacture. I believe my vehicle is showing possible premature bonding agent issues below the surface of panel. Where the manufacture bonding glue is causing interior flaking and cracking and lifting from the stress of the wrong/incorrect specified bonding material not used during the manufacturing process . I am afraid that while driving my vehicle at highway speed has the opportunity / potential for my panel to eventually break off and cause damage of flying panel pieces to harm myself or other vehicles traveling on the road. I believe the wrong bonding material is also causing other issues with the panel and the workmanship material used. My vehicle falls under the year, make, W222 and I am already seeing issues with my panel that by being proactive on my vehicle then reactive. I don’t want to wait for my panel to fly off when early detection and rectification is the safest way/option. My second concern is that there has already been changing dates on this recall information sent out in 2017, 2019 and now 2021. I am worried!!
Electrical system, Structure, Forward collision avoidance, Jun 2, 2024, crash
I am wanting to add information to my original complaint. Tracking#11589822 When I called in the electrical issue to AAA the agent said this is a common problem on these cars. Next, I want to add photos the Mercedes of Fresno service department sent me during the 2nd time my car was taken in to be checked. I honestly don't remember off hand when the collision occurred, I have that paper work somewhere. I will find it and send it in also. I will also get paper work from the auto body place that fixed as much of the wiring that it could. There was also a video on line I will try to find again and send that in.
Structure, Forward collision avoidance, May 21, 2024, crash
While I was driving to work in a heavy rain my abs malfunction light came on in my car. I decided to take it to the Mercedes-Benz dealership in Fresno. They said it was the ABS module that needed to be replaced. After being in the shop for almost 3 weeks they said it was fixed. When I went to pick it up, the moment I turned it on the ABS malfunction light came on again. I was told that it was okay to drive and they would have somebody come check it out at my work the next day. My car went back into the shop for another week and they could not figure out what was wrong with it. They did take pictures and the second time I took it in they noticed a bunch of water underneath the floorboard. By this time, I had lost confidence in them fixing my car the manager basically kicked me off the lot and told me never to go back again. So I continued to drive my car since I was told it was okay first time they fixed it. Short while later, I rear-ended another car. The ABS system did not warn me that I was too close. When I took my car in to get the body work fixed I was also given a name of somebody who would be able to fix the electrical problems and insurance would pay for it. He was able to fix the ABS system but could not find where the short was that controlled the passenger seat and the driver side back seat window and for the needle that tells me if my car is overheating. Nobody could figure out where the water had been coming from. It wasn't until recently when we just had a heavy storm that I noticed water leaking from inside the car through a seam. The running boards on the top of my car were not installed correctly so water seeps in there during rains and then it travels down underneath my floorboards and sits which was the cause of the shorts in my electrical system. My concern is that I don't know how bad other components of the car might be that one of the wires might at any of the wires might short while I'm driving now but unable to download receipts which I have
Structure, May 3, 2024
The contact owns a 2018 Mercedes-Benz C300. The contact stated while driving at approximately 65 MPH, there was a windy sound coming from the front of the vehicle. The contact then noticed the sound of an impact on the rear driver's side of the vehicle. The contact pulled to the side of the road and noticed that the front roof panel had separated and had struck the rear driver's side of the vehicle above, the wheel. The contact was able to continue driving. The vehicle was taken to an unknown dealer, where it was determined that the failure was related to NHTSA Campaign Number: 23V854000 (Structure) however, the VIN was not included. The dealer informed us that the repair would be an out-of-pocket expense. The insurance company towed the vehicle to an independent mechanic for the repair. The vehicle was being repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was unknown.
Structure, Oct 25, 2023
The contact owns a 2018 Mercedes-Benz C300. The contact stated while attempting to close the sunroof, the sunroof failed to close properly. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 21V197000 (Structure) but the VIN was not included. The manufacturer was notified of the failure, and a case was opened. The failure mileage was 45,000.
Visibility/wiper, Structure, Aug 12, 2023
Incorrect bonding of the rear window. The rear window bond is failing which is causing the window to detach from the convertible top. The bonding is failing in many different locations, causing not only detachment, but the failure is also causing fine hairline cracks at the points of failure. The dealership refused to correct the defect, informed I would have to pay $3,000.00 to correct the failure of the bonding.
Structure, Other or unspecified, Jan 29, 2023
This is 2018 Mercedes Benz - C300 and it seems across this model line up and models from that year it looks like headliner particularly fabric starts to separate from the pillars in the rear. Across google there is bunch of C300 with the same issue in the same spot starting. The Car is only 5 years old and if it would be any other brand I would not be to upset about it. But this is Mercedes and they pride themselves of being a " Luxury " Vehicle where their standards should be much higher. Needles to say we contacted and went to one of the Mercedes Dealership that we got charged $226 for the inspection and Mercedes did not honored to replace the defect nor MBUSA - did not helped either. This is the problem across the model . Be AWARE and take this into consideration when thinking of purchasing this particular model year C300.
Structure, Service brakes, Forward collision avoidance, Apr 25, 2021
DATE: APRIL 13, 2021. MODEL: C300 YEAR : 2018 MILAGE: 16,000. TIME: 2.30 P.M. WHETHER: SUNNY. ROAD CONDITION: SMOOTH PROBLEM: WHILE DRIVING ON 405 SOUTH AT SPEED OF APPROX 65 TO 70 MPH FOR NO APPARENT REASON , THE CAR UDDENLY , UNEXPECTEDLY, AND FORCEFULLY SLAMMED ON THE BRAKES ( 65 TO 0 MPH) IN MATTER OF SECONDS, AND LOCKED ITS WHEELS. LEFT ME STOCK ON THE FWY. THE MOST SCARIEST EXPERIENCE AS YOU DON'T KNOW WHAT IS GOING ON OR WHAT IS GOING TO HAPPEN TO . LUCKILY THERE WERE NO VEHICLES IN MY CLOSE PROXIMITY OR WE COULD HAVE DIED ! THE WARNING SIGNS WERE ON " INOPERATIVE BREAK ASSIST SYSTEM" . THE CARS FORCE WAS SO STRONG THAT NOT ONLY JOLTED MY HEAD BACK AND FORTH, IT CAUSED MY COMPUTER TO FLY FROM THE BACK SEAT AND HIT MY HEAD IN THE FRONT SEAT. I HAD TO REPLACE THE VEHICLES SENSORY RADAR ABOUT FOUR MONTHS AGO BACK IN NOV 2020. I SEE THAT MBZ HAS RECALLED ITS 2019 MODELS AND MANY OTHER MODELS ( SOFTWARE GLITCH THAT CAN SLAM THE BREAK UNEXPECTEDLY). WHY RECALL C300 2019 AND NEWER MODELS AND NOT ALL MODELS WITH THIS DEFECTIVE SENSOR SYSTEM.. IT WILL TAKE THEM 30 MINUTES TO REPROGRAM EACH CARS SOFTWARE, YET, ARE NOT DOING IT AND ENDANGERING THE PUBLIC. WHAT HAPPENED TO ME WAS A VERY SCARY INCIDENT AND HOPE THAT YOU CAN GET THEM TO RECALL MY VEHICLE . I AM SCARED TO DRIVE IT AGAIN AS IT COULD HAPPEN AGAIN!
Structure, Sep 12, 2018
TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ C300 CONVERTIBLE. THE CONTACT STATED THAT THE FRONT PASSENGER SIDE FENDER BECAME PARTIALLY DETACHED FROM THE BODY OF THE VEHICLE. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF FORT WASHINGTON (404 PENNSYLVANIA AVE, FORT WASHINGTON, PA 19034, (215) 646-7700) AND THE CONTACT WAS CHARGED FOR THE REPAIR ON A FAIRLY NEW VEHICLE. THE MANUFACTURER WAS NOT CONTACTED. THE FAILURE MILEAGE WAS 7,650. THE VIN WAS UNKNOWN.
Structure, Jul 31, 2018
TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ C300. THE CONTACT RECEIVED NOTIFICATION OF NHTSA CAMPAIGN NUMBER: 18V456000 (STRUCTURE); HOWEVER, THE PARTS TO DO THE REPAIR WERE UNAVAILABLE. THE CONTACT STATED THAT THE MANUFACTURER EXCEEDED A REASONABLE AMOUNT OF TIME FOR THE RECALL REPAIR AS THE RECALL NOTICE WAS RECEIVED OVER THREE WEEKS AGO. THE DEALER (MERCEDES-BENZ OF ONTARIO, 3787 E GUASTI RD, ONTARIO, CA 91761) WAS CONTACTED AND CONFIRMED THAT THE PARTS WERE NOT AVAILABLE FOR THE RECALL REMEDY. THE MANUFACTURER WAS NOT NOTIFIED. THE CONTACT HAD NOT EXPERIENCED A FAILURE. THE VIN WAS NOT AVAILABLE.