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Mercedes CLK Turbo Issues

My 2005 Mercedes CLK with a gasoline engine is giving me trouble. It has 112961 km on it. The check engine light is on, and the performance is terrible. Engine power is way down, and the response is just awful. There's also a whistling noise and a loud hissing sound that seems to be coming from the turbo when I accelerate. Sometimes the engine stalls when idling, and I've noticed I'm using more fuel. I think it might be a bad electrical bypass valve for the turbo wastegate or actuator. Has anyone else had this happen? Any ideas before I get a big repair bill?

4 comment(s)

That sounds familiar. I had similar symptoms on my CLK. Check the turbocharger pressure sensor and the connections to the turbo actuator. A faulty sensor or a leak in the vacuum lines can cause these issues. Is the hissing constant or only when the engine is working hard?

The hissing is definitely louder when the engine is working harder. I hadn't thought about the pressure sensor. Where is it located, and how hard is it to test?

Okay, hissing when the engine is working hard suggests a leak in the turbo system. The pressure sensor is usually on the intake manifold or near the turbocharger. You'll need a multimeter and some electrical testing knowledge to test it. It might be better to have a workshop check it.

I took it to the workshop as you suggested, and they confirmed it was a problem with the electrical bypass valve, which caused the turbo actuator to fail. The repair cost me 250€, but the car is running well again. Thanks for pointing me in the right direction.

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