Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2016 Mercedes-Benz GLC300 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2016 Mercedes-Benz GLC300. The contact stated that while driving 45-50 MPH, the engine experienced rough idling and the vehicle was shaking violently. Several unknown warning lights were illuminated. The contact pulled over and turned off the vehicle. The vehicle was towed to an independent mechanic, who determined that cylinder #1 had a cracked piston and the engine needed to be replaced. The vehicle was then towed to another independent mechanic, who also determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure, but no assistance was provided. The failure mileage was approximately 90,000.
The contact owns a 2016 Mercedes-Benz GLC300. The contact stated that the check engine warning light was illuminated. The vehicle was taken to dealer, where it was diagnosed that the crankcase ventilation system needed to be replaced. The vehicle was repaired; however, the failure reoccurred. The vehicle was taken back to the dealer, where the diagnostic result was confirmed. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was opened. The failure mileage was approximately 30,000. The VIN was unavailable.
The contact owns a 2016 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the check engine warning light remained illuminated. The vehicle was taken to the local mechanic who diagnosed that the crank case ventilation sensor was faulty and needed to be replaced. The vehicle was not repaired. The local dealer was not contacted. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was 70,000.
Piston 1 cracked while driving on the highway. My sibling was driving on the highway when the engine suddenly started misfiring and losing power because it lost compression on the piston that cracked. I was lucky enough that I have mechanic experience to replace all the damaged components myself and paid out of pocket. I was super fortunate that the cylinder walls did not get damaged when this happened thus not needing an entire engine replacement which would cost around $10,000 from mercedes. I had to go pick up a trailer from UHaul and go pick up the vehicle from where it broke down. Thinking about this from the perspective of a person who does not have access to rent a trailer, a vehicle to pull said trailer with, or the mechanic experience to fix the vehicle themselves, the cost to get this issue resolved would be much much more than it cost me.
While driving on the NYS Thruway last week, when I accelerated to pass another car, my engine bucked and kicked followed by the "check engine" light coming on.In very heavy traffic, I was able to pull to the shoulder. I called my service garage and they suggested I not drive the car for safety reasons. When the tow truck arrived, I briefly started the car with the same bucking and kicking from the engine. The car was taken to my regular garage where the "check engine" codes showed issues with the fuel injector and fuel injection system. I was told there is an existing RECALL CAMPAIGN # 2022030003 for the same year, make and model as mine but, my VIN is not part of that RECALL. I would like your help as I do not believe Mercedes-Benz is being fair or equitable in this RECALL. ThankYou
Got a Check Engine Light at 32,400 miles and the code said it was the Positive Crankcase Ventilation Regulatory Valve. It was under warranty, the job requires over 6 hours of labor, and it's due to a intake breather valve getting gummed up with oil/oil vapors/condensation. Well, the check engine light came on again at 58,000 miles and 3 years later. Now not under warranty, the dealer quoted 6 hours and $1435 to do the same repair that was done before. The part is EXTREMELY difficult to get to in order to change, and requires the removal of many engine components, including one of the engine mounts. It seems like this is one of the most common repairs for this series of car. It's been so troublesome, that Mercedes has redesigned the part.
While operating the vehicle at highway speed, the Check Engine Light illuminated on the vehicle dashboard and remained constant. The associated malfunction code(s) displayed were P052E71 (actuator blocked) as well as P06DA00 (electrical-open circuit). The vehicle is available for inspection upon request. The vehicle emitted pungent odor and fumes into the cabin and demonstrated sudden decreased acceleration and rough idling. The problem has yet to be inspected by the manufacturer as it is not sure whether it is safe to operate. No other warning lamps illuminated prior to the failure. Unsure if cold start failure is a symptom associated with current issue or if an electrical problem related to prior recall.
The contact owns a 2016 Mercedes-Benz GLC300. The contact stated while driving at an undisclosed speed, the check engine warning illuminated. The contact stated that the vehicle was taken to the Emissions Center, and the vehicle failed the Emissions test. The vehicle was taken to the dealer to be diagnosed. The dealer retrieved DTC: P052E (PCM has detected an inappropriate degree of pressure from the crankcase pressure sensor). The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was unknown.
I lost power on while driving at speed and almost got rear-ended before pulling over. I had to tow the car to a mechanic. After diagnosis it turned out the pistons are cracked and had to be replaced as well as the rod bearings. The pistons have a very abnormal burn pattern and rod bearing wear per my mechanic. This is a beautiful car and I take above average care of it. No car sold in the US should have pistons crack at such a short amount of miles. I believe Mercedes Benz should be held liable for their engineering error.
Got the MIL obd2 error code P052E - Positive Crankcase Ventilation Regulator Valve Performance. After some research this seems to be a common issue for this vehicle and other similar Mercedes Benz vehicles with the same engine. It is something that it is extremely expensive to fix (+$1500) and very labor intensive. I believe that Mercedes Benz should recall these vehicles and replace the Intake line due to its constant failure on many vehicles including mine.
Engine complaints in other GLC300 years
Frequently asked questions
How common are engine problems on the 2016 Mercedes-Benz GLC300?
NHTSA has 42 complaints about the engine & cooling of the 2016 Mercedes-Benz GLC300, 32% of the model year's 133 complaints. The component named most often is exhaust system › emission control › crankcase (pcv) (2 mentions).
Is there a recall for 2016 Mercedes-Benz GLC300 engine problems?
No. NHTSA lists no engine & cooling recall for the 2016 Mercedes-Benz GLC300, though it has 12 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2016 Mercedes-Benz GLC300 engine problems start?
Half of the complaints with a recorded mileage happened before about 28,000 miles, and 50% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 2 fires and 1 injury to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
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.