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daniel_mond1

Mercedes SLC Engine Power Loss and Noise

My 2016 Mercedes SLC gasoline engine with low mileage has a check engine light and reduced power. Engine response is poor, and it sometimes stalls. Fuel consumption is up, and there's a whistling sound that becomes a loud hiss when I accelerate. I suspect a wastegate valve issue. Could the turbocharger be failing, or could a faulty throttle body cause this?

Summary of the thread

A 2016 Mercedes SLC with low mileage experienced engine power loss, poor response, stalling, increased fuel consumption, and a whistling noise turning into a hiss during acceleration. The initial suspicion was a wastegate valve issue, with potential causes including a failing turbocharger or a faulty throttle body. After professional diagnosis, the problem was confirmed to be a defective wastegate valve, which was repaired, restoring the vehicle's performance.

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4 comment(s)

maryblitz75

Whoa, that sounds rough! A whistling turning into a hiss when you put your foot down? That's not good. It's like when you're blowing up a balloon and it suddenly gets a hole – all that air escaping! I'm no expert, but could be a leak somewhere in the turbocharger system? Have you checked all the hoses and connections? Maybe something's come loose?

daniel_mond1 (community.author)

I appreciate the analogy. I have visually inspected the hoses, but I haven't done a pressure test. Could a minor leak really cause these symptoms, especially the stalling and increased fuel consumption? I'm trying to figure out if a hose replacement will fix it, or if the wastegate is the problem.

maryblitz75

Okay, you've done some checking. Honestly, with all those symptoms – the stalling, the fuel economy taking a dive and the noise – it sounds like more than a loose hose. That wastegate thing you mentioned sounds plausible. My advice? Get it to a decent workshop. They'll have the right tools to diagnose the boost pressure system. Could save you headaches, and money!

daniel_mond1 (community.author)

Thank you for your input. A professional diagnosis was indeed warranted. The issue was a defective wastegate valve, as suspected. The repair cost 860€. The vehicle is now performing optimally. Your assistance is appreciated.

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MERCEDES

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SLC