There are 4 owner-reported engine complaints for the 2020 Mercedes-Benz GLB-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Diagnostics performed and found electrical/component fault and possible wire damage to fuel pump. NECC to drain tank and inspect replace fule pump if necc. Oringally took one week prior and diagnostics led to the possiblility that the cylinder head was malfunctioning, which was a manufacturing defect and covered under an extended warranty, but now advised otherwise. Quote $2200.00. Mileage on vehicle 23,660.
Car constantly cuts out and loses power as well as occasionally shuts off for no reason. Causing very hazardous driving conditions. I have noticed that this is a common issue stated in online forums with this particular car as well. It is more times than not an issue with the engine head and valves.
The engine made a knocking sound and i pulled over on the side of the road took the car to MB dealership to get the recall fixed but i was told the recall cannot be fixed until the engine is fixed. MBUSA refuses to replace the engine even though it is fully covered under warranty. Thus because i cannot get a recall done for my safety unless i get an engine replaced. This is absolutely horrible. MB knows they produced a bad engine and are forcing us to pay out of our pocket then they will fix the recall on the car.
Engine failure. Engine has no compression which is causing injection fueler to fail. The head engine has gone bad at 50,000 miles. Head engine must be replaced and is on back order per Mercerdes Benz. After research on the issue I’ve noticed the Year/Make/Model this is issue is common at the 40k-50k mile mark. This is a manufactured issue that Mercerdes needs to fix if so common within the car and also unsafe. Not okay for a new car to have engine failure this early
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026