This Problem Across All Years
I purchased this 2020 Mercedes-Benz C300 only two months ago and have driven it less than 3,000 miles. The Carfax report shows consistent maintenance and regular service history by prior owners. While driving, the check engine light came on and the vehicle began shaking and running roughly. Diagnostics by Peachtree Imports (10/03/2025) and later by Mercedes-Benz of Atlanta South confirmed Cylinder #2 failure on the M264 2.0L engine at only 26,589 miles. The dealer’s report states: “Cylinder #2 mixture formation out of spec. Fault occurred due to worn exhaust valve seat. Cylinder head replacement required.” Estimated repair cost: $10,470.66. This causes misfire, loss of power, and unsafe drivability. The failure matches Mercedes-Benz Technical Service Bulletin LI01.30-P-072328 (2021), which documents valve-seat leakage in M264 engines requiring head replacement. The vehicle is outside warranty but has extremely low mileage, and MBUSA Case #18392667 remains unresolved. It is also important to note that the M260 engine, which is mechanically identical to the M264 but mounted transversely, has already received a warranty extension from Mercedes-Benz for the same cylinder-head and valve-seat defect. This indicates a systemic issue across both engine families, presenting a safety risk of sudden power loss or engine stall during operation.
I purchased this 2020 Mercedes-Benz C300 only two months ago and have driven it less than 3,000 miles. The Carfax report shows consistent maintenance and regular service history by prior owners. While driving, the check engine light came on and the vehicle began shaking and running roughly. Diagnostics by Peachtree Imports (10/03/2025) and later by Mercedes-Benz of Atlanta South confirmed Cylinder #2 failure on the M264 2.0L engine at only 26,589 miles. The dealer’s report states: “Cylinder #2 mixture formation out of spec. Fault occurred due to worn exhaust valve seat. Cylinder head replacement required.” Estimated repair cost: $10,470.66. This causes misfire, loss of power, and unsafe drivability. The failure matches Mercedes-Benz Technical Service Bulletin LI01.30-P-072328 (2021), which documents valve-seat leakage in M264 engines requiring head replacement. The vehicle is outside warranty but has extremely low mileage, and MBUSA Case #18392667 remains unresolved. It is also important to note that the M260 engine, which is mechanically identical to the M264 but mounted transversely, has already received a warranty extension from Mercedes-Benz for the same cylinder-head and valve-seat defect. This indicates a systemic issue across both engine families, presenting a safety risk of sudden power loss or engine stall during operation.
I own a 2020 Mercedes-Benz C300, and the check engine light recently came on. The vehicle has only around 27,000 miles and has been regularly maintained at an authorized dealership. Diagnostic testing revealed fault code P06DA00, indicating an electrical failure or open circuit in the engine oil pump control valve. The dealership confirmed that the valve could not actuate and provided a repair estimate exceeding $7,000 due to the labor-intensive nature of the repair. This issue occurred shortly after the factory warranty expired. The sudden loss of power while driving could pose serious safety risks under different traffic conditions. I believe this may be a manufacturing defect that could potentially affect other vehicles of the same model. This issue occurred shortly after the factory warranty expired. The way the vehicle lost power suddenly while driving could have posed serious safety risks in different traffic conditions. I believe this could be a manufacturing defect and may affect other vehicles of the same model.
I own a 2020 Mercedes-Benz C300, and the check engine light recently came on. The vehicle has only around 27,000 miles and has been regularly maintained at an authorized dealership. Diagnostic testing revealed fault code P06DA00, indicating an electrical failure or open circuit in the engine oil pump control valve. The dealership confirmed that the valve could not actuate and provided a repair estimate exceeding $7,000 due to the labor-intensive nature of the repair. This issue occurred shortly after the factory warranty expired. The sudden loss of power while driving could pose serious safety risks under different traffic conditions. I believe this may be a manufacturing defect that could potentially affect other vehicles of the same model. This issue occurred shortly after the factory warranty expired. The way the vehicle lost power suddenly while driving could have posed serious safety risks in different traffic conditions. I believe this could be a manufacturing defect and may affect other vehicles of the same model.
My wife was driving our 2020 Mercedes Benz C300 coupe near our house and the engine light came on. Then the car could not be driven over the speed of 30 miles per hour. Then it stopped and had to be towed. Fortunately, she was able to avoid being hit by other vehicles.The car only has 25219 miles. It was towed to a mechanic who performed a diagnostic test which provided a series of codes regarding the malfunction. Three codes were related to the CAMTRONIC camshaft system and its Solenoid ( Codes: P003C-53; P34AE-00; P34AD-09). Camshaft position actuators Failure codes: P34AD; P34AE. The way it happened could have resulted in damage, serious injury or death since the car suddenly stopped. The car is well maintained. We believe that there is a manufacturer's defect since this is a garaged vehicle that is well maintained and has low mileage.
My wife was driving our 2020 Mercedes Benz C300 coupe near our house and the engine light came on. Then the car could not be driven over the speed of 30 miles per hour. Then it stopped and had to be towed. Fortunately, she was able to avoid being hit by other vehicles.The car only has 25219 miles. It was towed to a mechanic who performed a diagnostic test which provided a series of codes regarding the malfunction. Three codes were related to the CAMTRONIC camshaft system and its Solenoid ( Codes: P003C-53; P34AE-00; P34AD-09). Camshaft position actuators Failure codes: P34AD; P34AE. The way it happened could have resulted in damage, serious injury or death since the car suddenly stopped. The car is well maintained. We believe that there is a manufacturer's defect since this is a garaged vehicle that is well maintained and has low mileage.
Cylinder head is defective. Service advisor told me it was a known issue in which exhaust valves within cylinder head are prone to premature wear. If left unaddressed it leads to inevitable engine failure. I was quoted $12,000. My car is 2020 model year with not even 60,000. Barely even 4 years old.
Cylinder head is defective. Service advisor told me it was a known issue in which exhaust valves within cylinder head are prone to premature wear. If left unaddressed it leads to inevitable engine failure. I was quoted $12,000. My car is 2020 model year with not even 60,000. Barely even 4 years old.
MY 2016 C300 (IN-LINE 4 TURBO, "PETROL" WITH 241HP) AT 55K MILES HAD 1ST CYLINDER CRACKED WHILE DRIVING ON HIGHWAY, AND MY CAR IS OUT OF WARRANTY. I TALKED TO MY DEALERSHIP AND THE CORPORATE SEPARATELY. THE DEALERSHIP WOULD COVER THE COST OF THE PARTS WHETHER THE ENGINE NEEDS REPLACEMENT OR NOT, AS I BOUGHT MY CAR THERE NEW AND HAVE BEEN USING THEM THROUGH PREPAID MAINTENANCE. I DECIDED TO FIX THE CAR AND PAY THEM PRE-ARRANGED LABOR. BUT HERE IS THE RESPONSE FROM THE CORPORATE: THANK YOU FOR YOUR EMAIL TO MERCEDES-BENZ USA, ALTHOUGH WE REGRET TO LEARN OF THE CIRCUMSTANCES THAT PROMPTED YOUR CONTACT. WHILE WE UNDERSTAND YOUR CONCERNS, ALL WARRANTY DETERMINATIONS ARE PROVIDED BY AN AUTHORIZED MERCEDES-BENZ DEALERSHIP UPON INSPECTION. IF THE WARRANTY HAS EXPIRED, THERE IS NO OBLIGATION ON PART OF THE MANUFACTURER, TO COVER THE COST OF REPAIRS. CUSTOMERS CAN REQUEST GOODWILL ASSISTANCE, HOWEVER WHICH IS REVIEWED ON A CASE BY CASE BASIS AND NOT GUARANTEED. IT MAY BE HELPFUL FOR YOU TO KNOW THAT WHEN REVIEWING YOUR CONCERN, THE VEHICLE REQUIRES AN INSPECTION AT AN AUTHORIZED MERCEDES-BENZ DEALERSHIP, AND THE FOLLOWING VARIABLES WOULD BE TAKEN INTO CONSIDERATION: VEHICLE AGE, MILEAGE, VEHICLE HISTORY, SERVICE/REPAIR HISTORY (WHETHER MAINTENANCE IS PERFORMED AT MB DEALERS), AND BRAND LOYALTY. REVIEW FOR GOODWILL REQUESTS CAN ONLY BE REVIEWED PRIOR TO REPAIRS BEING PERFORMED, AS REIMBURSEMENT IS NOT POSSIBLE. WE APPRECIATE THE OPPORTUNITY TO RESPOND. THERE MAY BE MORE CASES AS SHOWN ON THIS FORUM: HTTPS://MBWORLD.ORG/FORUMS/C-CLASS-W205/731642-W205-C300-STAY-AWAY-PISTON-CRACKED-65-K-MILES-5.HTML
MY 2016 C300 (IN-LINE 4 TURBO, "PETROL" WITH 241HP) AT 55K MILES HAD 1ST CYLINDER CRACKED WHILE DRIVING ON HIGHWAY, AND MY CAR IS OUT OF WARRANTY. I TALKED TO MY DEALERSHIP AND THE CORPORATE SEPARATELY. THE DEALERSHIP WOULD COVER THE COST OF THE PARTS WHETHER THE ENGINE NEEDS REPLACEMENT OR NOT, AS I BOUGHT MY CAR THERE NEW AND HAVE BEEN USING THEM THROUGH PREPAID MAINTENANCE. I DECIDED TO FIX THE CAR AND PAY THEM PRE-ARRANGED LABOR. BUT HERE IS THE RESPONSE FROM THE CORPORATE: THANK YOU FOR YOUR EMAIL TO MERCEDES-BENZ USA, ALTHOUGH WE REGRET TO LEARN OF THE CIRCUMSTANCES THAT PROMPTED YOUR CONTACT. WHILE WE UNDERSTAND YOUR CONCERNS, ALL WARRANTY DETERMINATIONS ARE PROVIDED BY AN AUTHORIZED MERCEDES-BENZ DEALERSHIP UPON INSPECTION. IF THE WARRANTY HAS EXPIRED, THERE IS NO OBLIGATION ON PART OF THE MANUFACTURER, TO COVER THE COST OF REPAIRS. CUSTOMERS CAN REQUEST GOODWILL ASSISTANCE, HOWEVER WHICH IS REVIEWED ON A CASE BY CASE BASIS AND NOT GUARANTEED. IT MAY BE HELPFUL FOR YOU TO KNOW THAT WHEN REVIEWING YOUR CONCERN, THE VEHICLE REQUIRES AN INSPECTION AT AN AUTHORIZED MERCEDES-BENZ DEALERSHIP, AND THE FOLLOWING VARIABLES WOULD BE TAKEN INTO CONSIDERATION: VEHICLE AGE, MILEAGE, VEHICLE HISTORY, SERVICE/REPAIR HISTORY (WHETHER MAINTENANCE IS PERFORMED AT MB DEALERS), AND BRAND LOYALTY. REVIEW FOR GOODWILL REQUESTS CAN ONLY BE REVIEWED PRIOR TO REPAIRS BEING PERFORMED, AS REIMBURSEMENT IS NOT POSSIBLE. WE APPRECIATE THE OPPORTUNITY TO RESPOND. THERE MAY BE MORE CASES AS SHOWN ON THIS FORUM: HTTPS://MBWORLD.ORG/FORUMS/C-CLASS-W205/731642-W205-C300-STAY-AWAY-PISTON-CRACKED-65-K-MILES-5.HTML