Black smoke and fading power under load on a GLE V167 diesel usually point to a clogged EGR or DPF. This guide tells you what to inspect first, what often can be cleaned, and whether it’s safe to keep driving.
Why Your GLE V167 Loses Power and Blows Black Smoke
When your Mercedes GLE V167 diesel, typically the OM656 engine in this generation, loses power exactly when you accelerate hard and leaves a black haze behind, the engine is telling you that fuel is not being burned cleanly. Black smoke is unburned carbon and load makes it worse. The most common causes on this platform are EGR valve and cooler problems that let too much exhaust gas back into the intake, or a DPF that's become restricted enough to choke the turbo and the whole breathing system. On many GLE V167s, a coked, sticking EGR valve throws off the mixture, and a heavily sooted DPF raises exhaust backpressure until the turbo just can't deliver the air the engine needs.
