Problems after changing turbo

Hi All,

Im desperate for some help. I recently had my turbo changed on my Mercedes C200 diesel after the shaft broke. After the change I have had a problem that will not go away. It occasionaly over and underboost, overboost to a point where i blew the pressure hose that goes from the intercooler, after I changed it it with a new hose ripped the housing the hose goes into apart, meaning serious pressure. On the other hand, sometimes it underboost. If i go fast and then come to a stop and start in frist gear it feels like it’s not boosting at all and crawling away with 1/3 of the power, if I then let go of the gas and give gas again the boost is back and goes like it should. After the turbo change, I have changed hoses from intercooler, I have changed the intercooler, several sensors but nothing works. Next step is changing the turbo once more, rather not go there if there is something else, I can do. Any help would be highly appreciated.

BTW im on my 4th mechanic now, they tell me every time now it’s fixed and I pay them in the thousands and hope not so far no luck.

Hope to get help

Best Nicolai

Sounds to me like your wastegate isn’t working right. It could be intermittently sticking or the controller could be sending it bad commands.

If the wastegate sticks open you won’t get any boost. If it sticks closed you’ll overboost.

what year is your car? how many miles? is it worth spending thousands of dollars on? it is what it is. i imagine you did not plan on spending lots of money at first. a broke turbine sends metal into the intercooler and than no bits were sent into the motor itself? as the condition of the motor is good?

You did not say what year this thing is or where you are located so you might be in an area that does not have a lot of Mercedes diesel trained mechanics. This sounds like a case for using a Mercedes dealer.

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First off, I’m not a Benz guy much at all. Other than a waste gate issue I wonder if this car uses an over boost switch such as SAABs used? If so,maybe there’s an issue with the switch, wiring, etc.
Just some wild guessin’…

A diesel has different boost control methods vs a gas motor