Mercedes GLK Diesel Engine Issue

I had similar symptoms with my GLK. A faulty crankcase ventilation valve can cause those issues. The system relieves pressure and removes harmful gases. When the valve fails, it can disrupt this, leading to increased pressure, oil leaks, and blueish smoke. Reduced power results from the engine not breathing correctly, affecting the emissions system and triggering the check engine light. I'd investigate this first.

When yours was doing this, did you notice any specific noises or anything else that might help confirm it's the crankcase ventilation? I'm trying to avoid just throwing parts at it without being reasonably sure.

I didn't experience any specific noises, but the smoke and power drop were key indicators. Given the potential impact on emissions and engine performance, and considering the mileage, I suggest a qualified technician diagnose it to confirm the valve's functionality and avoid further complications. Running the engine with a bad valve can lead to more costly repairs.

Appreciate the advice. The shop confirmed the crankcase ventilation valve was the problem. Repair cost around 360€. Thanks again for the help!