benjaminfire10

GLC Engine Issues and EGR Valve Suspicions

My 2023 Mercedes GLC with a gasoline engine is exhibiting some concerning issues at 286991 km. I'm experiencing reduced engine power, the check engine light is on, smoke appears during acceleration, the engine runs rough, fuel consumption is higher, and there's jerking during acceleration, accompanied by a loud hissing sound. Suspect EGR valve. Any similar experiences?

4 comment(s)

I had similar symptoms on my GLC, though I have diesel engines. Reduced power and a rough idle were the first signs, then the check engine light. The hissing sound suggests a vacuum leak, often linked to the EGR valve system. Have you checked for any obvious leaks in the hoses around the valve? A malfunctioning EGR valve can definitely cause increased vehicle emissions.

I haven't checked for leaks myself. Where exactly should I be looking around the EGR valve? Is it easy to identify the hoses?

Without seeing your engine, it's hard to be precise. Generally, look for small vacuum hoses connected to the EGR valve and intake manifold. Cracks or looseness are common. However, given the symptoms, especially the smoke, a defective or jammed EGR valve is highly probable. A workshop diagnosis is recommended.

Thanks for the input. Took it to a workshop. The EGR valve was indeed the problem. Replacement cost 355€. Appreciate the confirmation.

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