LOUD ENGINE KNOCKING WHEN ENGINE IS COLD. DIAGNOSED AS INCORRECT/UNFAVORABLE TOLERANCES OF PISTON WRIST PINS THAT WILL ULTIMATELY LEAD TO ENGINE FAILURE. DIAGNOSIS HAPPENED WITH ODOMETER AT 2,438 MILES.
2015 mercedes-benz C-Class engine problems
moderate 97 complaints filed with NHTSA · avg repair $3,100
Complaints
97
Recalls
0
Crashes
0
Avg fix
$3,100
What owners are reporting 7 most recent
The dealership is staying I have an issue with the crankcase valve vent and this seems to be a known issue effecting years 2015-2018.
TL* THE CONTACT OWNS A 2015 MERCEDES-BENZ C300. THE CONTACT STATED THAT THE ENGINE HAD BEEN SHUTTING OFF EVER SINCE THE VEHICLE WAS PURCHASED IN 2016. IN ADDITION, SEVERAL UNKNOWN WARNING INDICATORS WOULD ILLUMINATE FOR NO REASON. MERCEDES-BENZ OF GEORGETOWN (7401 S INTERSTATE 35, GEORGETOWN, TX 78626, (512) 930-6150) STATED THAT THE ENGINE WAS DEFECTIVE. THE DEALER STATED THAT THEY PREVIOUSLY REP…
2015 Mercedes C300 crankcase ventilation regularly valve is garbage, have to spend around $2K to get it replaced. Very common issue for this model.
BOUGHT USED MERCEDES C300 2015 4MATIC ON FEB'2019, ODOMETER READING WAS 44K MILES WITH CLEAN CARFAX REPORT. AFTER DRIVING JUST ABOUT 7K MIKES MORE, AT 53K MIKES CAR SHOWS ENGINE WARNING. THIS IS UNFORTUNATE FROM MERCEDEZ THAT WITH THIS MUCH OF NIRMAL USE, CAR IS HAVING ENGINE ISSUES.
WHILE THE VEHICLE IN MOTION, HEARING A LOUD SOUNDS COMING FROM THE ENGINE. AT FIRST IT'S SOUNDED LIKE A ROCK IN A TIN CAN, LATER IT WAS A SLAPPING SOUND. ABOUT 10 MINUTES LATER FINALLY GOT OFF THE HIGHWAY AND TURNED IN TO MY NEIGHBOR HOOD. AT THE LAST RIGHT TURN, THE CAR SEIZED UP. TRIED TO RESTART NOTHING HAPPENED. GOOD THING IT WAS AROUND 11PM THERE WAS NO TRAFFIC OR AS MANY CARS ON THE ROAD. IF…
The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving approximately 50-60 MPH, the #1 piston cracked. The contact stated that while his daughter was driving, the vehicle was shaking and smoking. The check engine warning light illuminated. The vehicle was towed to an independent mechanic and the contact was informed that the #1 piston was cracked, engine cooler, P0301 cy…
Common questions
How serious is the engine problem on the 2015 mercedes-benz C-Class?
It's a documented issue but not catastrophic. 97 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Other problem areas on this vehicle
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Severity ratings are derived from reported crashes, fires, injuries, and fatalities.
Repair cost estimates are independent-shop national averages and may differ in your area.
Some links on this page are affiliate links.