2021 MERCEDES-BENZ GLB 250 Engine Problems

Engine locked up while driving out of state on the interstate. Vehicle lost all power and engine stopped functioning. Managed to pull over and stop the vehicle on the side of the interstate. Had truck towed to repair shop where they diagnosed connecting rod/crankshaft bearing failure, as well as lifter and cylinder misfire/failure on cylinder 7. Metal shavings were discovered in the oil, and engine locked up and cannot be repaired. I am currently in the process of having the engine replaced, but yes currently an inspection can still be performed, and I can provide statements and diagnostics from the mechanic. This failure put myself and my family in a scary situation. The engine was shaking violently before it stopped functioning and this made the truck very difficult to steer, not to mention this was during rush hour and we were in heavy traffic moving at speeds of 70mph+. Luckily...

Engine showed signs of loss of power and excess noise. It was taken to dealership via MB roadside assistance. At the dealership, they diagnosed it with engine catastrophic failure due to metal parts found in the oil filter. At no time was the engine disassembled to ensure known defects and still under warranty parts were not the cause. Dealer estimated the repair to cost in excess of $22K. MBUSA was contacted and they made no efforts to make the situation whole. The cost estimated was for the complete engine replacement. An engine that only has 53k miles. Although all routine maintenance have been conducted, engine failure was certainly pre-mature. Issues exhibited were excessive engine vibration, loss of power and excess noise.

In April 2025, my 2021 Mercedes-Benz GLB 250 (81,000 miles) suffered repeated engine issues caused by a cylinder head failure. The dealer attempted a cylinder head replacement, but during their own test drive after repairs, the engine completely seized and failed again on their property. This indicates a severe defect in the engine assembly that risks sudden power loss while driving, which could cause an accident. Prior to the failure, there were warning messages about misfires and rough idle. The problem has been confirmed by an authorized Mercedes-Benz dealer and the car has been kept at their shop since April, with no resolution. I am concerned this is a recurring safety defect affecting other GLB 250 vehicles. The vehicle is available for inspection and remains undriveable due to the failed engine. I request NHTSA to investigate for possible safety-related design or manufacturing defects that could cause sudden engine seizure and...

Jerking and loud noise from the engine after attempting to accelerate from a red light stop. Vehicle is idling very roughly and almost sounds like a diesel engine. Check engine light came on. Inspection at the dealership found multiple faults for camshaft positions deviating from the specified value. When the oil filter was removed, the shop reported finding some metal particles in the oil. The conclusion was that a mechanical fault caused a metal part in the engine to brake and clog up the engine. The car did not run smoothly after the jerking sound and could have caused an accident if the car was in active motion. The recommendation now is that the engine needs to be replaced.

Cylinder Head gone bad at 35,000 miles

We purchased a brand new Mercedes GLB in January 2021, I noticed the car started to shake. On our way leaving Zion National Park, the car started shaking really hard and the engine light turned on. The car wouldn't accelerate. We had to pull over on the side of the road. We barely made it to the dealer in St. George, Utah, with the car shaking the entire time. We met with Ryan Poleszak the service adviser, and he said that he has seen this problem several times with Mercedes 4-cylinder engines in GLB, GLA, and C-class models in the past, and it looks like the car needs a new engine. After over 4 weeks and a lot of back & forth, we realized that he had no intention to fix our car. The dealer in the SouthBay told us that the dealer in St. George, Utah never registered the...