eliaswilliams1

Mercedes GT Roadster Engine Problem

My 2021 Mercedes GT Roadster with a gasoline engine is exhibiting some worrying symptoms. The check engine light illuminated recently, accompanied by a noticeable reduction in engine power and poor throttle response. I've also observed the engine stalling at idle, increased fuel consumption, and a distinct whistling noise, escalating to a loud hissing sound during acceleration. I suspect a fault within the boost pressure system, possibly a defect in the wastegate valve. The car has km on the clock. Could this be related to a faulty turbocharger or perhaps a leak in the intercooler system, affecting boost control? I am not seeing any error codes related to the throttle body.

A 2021 Mercedes GT Roadster is experiencing engine issues, including a check engine light, reduced power, poor throttle response, stalling, increased fuel consumption, and a whistling noise escalating to a hissing sound during acceleration. The suspected cause is a fault in the boost pressure system, possibly involving the wastegate valve or a leak in the intercooler system. After running a diagnostic scan, the problem was confirmed to be the wastegate valve actuator, which was repaired at a workshop, resolving the issues.

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4 comment(s)

Sounds like you're on the right track with the boost pressure system. The whistling and hissing, along with the power loss, definitely point in that direction. Have you checked the vacuum lines for any obvious cracks or leaks? A simple visual inspection there might reveal something. A faulty diverter valve could also cause similar issues, but I'd probably lean towards the wastegate valve as you initially suspected. Not sure though.

Thanks for the input. I did a quick visual check of the accessible vacuum lines, but nothing jumped out at me. Is there a reliable way to test the wastegate valve without specialized tools? I'm hesitant to start disassembling things without a clearer diagnosis. Any thoughts on whether a scan tool could pinpoint the problem more accurately before I consider replacing the turbocharger?

Testing the wastegate without proper tools could be tricky. A scan tool should give you some relevant codes related to boost pressure. It's probably worth getting the codes read before you start throwing parts at it. If it is the wastegate, replacing it might be beyond a simple DIY. You might want to consult a workshop.

Appreciate the advice. I ran a scan and it pointed towards the wastegate valve actuator. Took it to a shop, and they confirmed it. Repair cost was 860€. Car is running fine now.

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MERCEDES

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GTROADSTER