Engine complaints by model year
Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
What owners report
The contact owns a 2025 Mercedes-Benz GLC 300. The contact stated that while her husband was driving at 5 to 10 MPH attempting to park the vehilce lunged forward traveling 20 feet and crashed into the house. The air bags deployed. No warning lights were illuminated , There was no injuries or fire. A police report was filed. The gas company was on the scene due to a gas leak. Additionally the vehilce was serviced for electrical issues. While reversing in the snow the vehilce lunged 20 feet and crashed into a unknown vehicle causing a scratch. The local dealer was contacted where the EDR was requested. The vehicle was not diagnosed or repaired. The vehilce was towed to a towing lot. The manufacturer was not contacted The failure mileage was approximately 17,107. The vehicle was deemed a total lost.
I am writing to formally express my deep dissatisfaction and serious concerns regarding both my 2024 and 2025 Mercedes-Benz vehicles, purchased/leased through your dealership. I am now facing an unacceptable situation that not only violates my consumer rights but has repeatedly placed my personal safety in jeopardy. After significant issues with my original 2024 vehicle, I was provided a replacement, which I took delivery of on October 15, 2024. Unfortunately, within two weeks, the replacement vehicle was already back in the shop for repairs. It has since required service again on December 24, December 31, and most recently, May 28, 2025. On one particularly alarming occasion, the vehicle shut off in the middle of the road, creating an extremely hazardous and life-threatening situation. …
When stopped at a light or stop sign, Vehicle will Jerk forward as If hit from behind. Very surprising and dangerous. Very intermittent. The has happened many times. Vehicle will at times have rough downshifts. Ie. overdrive (9th) to (8th) gear. also intermittent. This has happened multiple times. Vehicle was taken to the dealer twice for a total of 50 hours in the shop. The first service time no problem was found, diagnostics did not show problem. Aug 22 to Aug 30, 2024. The second service time Oct 3 to Nov 14, 2024. Problem was duplicated by the technician. Vehicle diagnostics still did not show a problem. Technician replaced the transmission valve body, did various software checks at the request of the factory. The engine control unit was then changed based on data supplied to the factory. At this point technician checked the car and dealers believes car is fixed. …
While driving the vehicle the engine started running rough, check engine light illuminated and it would not accelerate above 40 mph. There are 29,100 miles on the vehicle, it's been serviced on schedule by Mercedes and is owned by me since new. It is especially concerning due to the acceleration topic which could have been catastrophic if I were trying to merge into traffic. Dealer service say the camshaft bearing needs to be replaced. It seems this is very premature for the mileage on the vehicle.
The contact owns a 2023 Mercedes-Benz GLC300. The contact stated while attempting to start the vehicle, the message "12 Volt Battery Failure, Vehicle Inoperative" was displayed. Later, the contact was able to start the vehicle, but the check engine warning light remained illuminated. Eventually the light shut off and the vehicle operated normally. The vehicle was taken to the local dealer who performed a diagnostic test and identified multiple communications errors however, the cause of the errors was not yet determined. The vehicle was not repaired. No further information was available. The manufacturer was notified of the failure. The failure mileage was 400.
Sunday, June 25, when I was driving the car on the road, the engine shut off and the car stopped running. 3 warning lights show on screen: engine light; 48v Battery Service Required; 12v Battery service required. I used the break to park the car on the roadside after that. I tried many times to restart the car, Waited over one hour and 40 minutes it finally started again, the engine warning light was still on until the second day morning, and I was able to take pics as evident. 1. What component or system failed or malfunctioned, and is it available for inspection upon request? Yes, but on the second day, the MB service dep told me that the car was having a system update (while I was driving the car and it turned off the engine by doing that) 2. How was your safety or the safety of others put at risk? I was still driving with 40m/h+ on the road, my car suddenly having a malfunction. 3. …
While driving on the [redacted] at the speed of 10 to 15miles per hour, I noticed a smoke in the from hood on the passenger side. I felt a danger and stopped the car and got out of the car immediately along with my friend, leaving my belongings phone and other documents etc. Immediately it caught up the fire. I called 911 and reported the incident. Police and Fire engine arrived and tried to stop the fire. I have sent out an email to the dealership as the vehicle is under guaranty and i haven't got any courtesy call to know about the incident. When i tried to call them they didn't even respond to me and hung the phone. I received a call from their sales department and enquiring about if i'm looking for any other vehicle which disappointed me more. I'm in shock and would like this to be investigated as this major security concern. …
The contact owns a 2022 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. There was a misfire coming from the engine, and the vehicle lost motive power. In addition, the check engine warning light illuminated. The vehicle was taken to the dealer, where it was diagnosed with spark plug failures, coils, and the transmission needed to be flushed. The vehicle was taken to an alternate dealer where the spark plugs and coils were replaced, and the transmission fluid was flushed. The contact stated that the failure reoccurred. …
Related recalls (2)
Engine and engine cooling › Critical fasteners
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2023 GLC300, 2024 GLE350, and GLE450 vehicles equipped with an M254 engine. The incorrect screws, installed on the high-pressure fuel pump, may prevent a proper seal from forming between the high-pressure fuel pump and the tandem oil pump.
Remedy: Dealers will replace the high-pressure fuel pump, free of charge. Owner notification letters were mailed February 9, 2024. Owners may contact MBUSA customer service at 1-800-367-6372.
Engine and engine cooling › Engine › Gasoline › Turbo/supercharger
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2020 C300, E350, and GLC300 vehicles equipped with turbocharged 4-cylinder gasoline engines. The screws that retain the turbocharger oil feed and return lines may not have been properly tightened, possibly resulting in an oil leak.
Remedy: MBUSA will notify owners, and dealers will inspect the turbocharger oil lines and tighten them as necessary, free of charge. The recall began August 17, 2020. Owners may contact MBUSA customer service at 1-800-367-6372.
Frequently asked questions
Which Mercedes-Benz GLC300 years have engine problems?
By NHTSA complaints, the 2016 (42), 2017 (37), 2021 (30), 2018 (28) and 2020 (21) model years. Engine complaints make up 32% of all complaints for the 2016.
Is there a recall for Mercedes-Benz GLC300 engine problems?
Yes — 2 recalls, including 23V-878 (critical fasteners, Dec 21, 2023); 20V-364 (turbo/supercharger, Jun 22, 2020). Recall repairs are free at authorized dealers; check a specific car with the VIN recall check.
At what mileage do Mercedes-Benz GLC300 engine problems start?
Across all years, half of the complaints with a recorded mileage happened before about 29,000 miles; 76% happened before 50,000 miles.
What part fails most often?
Owners most often name the exhaust system › emission control › crankcase (pcv) (2 mentions), followed by the engine › crank/camshaft position sensor (1).
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.