Esser

I've been having a problem with the wastegate on a 535d. Sometimes when you drive along, the car won't rev properly, and doesn't pull at all. It doesn't show any warning messages on the dash.
At most times though, it pulls like a train, as it's supposed to
I tried looking under the hood, and noticed that the arm and lever mechanism which is connected to the wastegate, seems to get stuck open sometimes!
When you rev the engine, you can clearly see that the arm moves forward, and then moves back, when you let off the throttle. But, sometimes, the arm moves forward when the engine is reved, and seems to stay there, when you let off the throttle. I think that could be the problem.

Has anyone ever experience anything like this, or know what could possibly be done to fix it?

zach1328

The 535i has waste-gate rattling issues and sometimes they get stuck open or shut too. BMW has an extended warranty on the n54 twin turbo engine for the waste-gates which is good for up to 8 years and 82,000 miles.
What is your mileage? I would check to see if the extended warranty applies to the 535d as well - or if there is a separate extended warranty for the diesel.

Esser

The car has done around 143.000 miles, so it's not exactly low mileage, but it has been VERY well looked after.

JasonH

The wastegate is vacuum controlled so you could have a vacuum leak (very very common on the 535d).

The pressure converter to the vacuum actuator could be on the way out (Pierburg part £40 or £80 ish from BMW).

Or the wastegate could simply be physically stiff - very likely. You can manipulate it by hand to feed it up. It's pretty stiff at the best of times.