Seized injector in Movano B 2.3 CDTI: how can it be removed without damaging the head?

Carbon building up around the injector acts like an adhesive. Over time it seizes the component in its seat so firmly that the injector cannot be removed by hand after its clamp has been undone. Trying to wrench it out can snap the injector body or tear the seat out of the cylinder head, resulting in a repair many times more expensive than the injector itself. The correct procedure requires a hydraulic injector puller screwed onto the injector body and patience. The injector is worked out gradually after the seat has first been soaked with penetrating fluid.

What must be done during installation?

Three steps determine whether the problem returns. First, clean the seat with a dedicated injector-seat cutter because carbon residue prevents the new washer from sealing evenly. Second, fit only new copper injector sealing washers and O-rings, and tighten the clamp to the specified torque and angle. Third, if the injectors have been replaced or reconditioned, their IMA codes must be programmed into the control unit. Without coding, the engine runs unevenly and smokes despite correct mechanical installation. The underlying cause should also be established. Prolonged blow-by past a worn washer accelerates seizure, so if diesel fumes were previously noticeable inside the cab, the seals on all injectors should be replaced rather than only those on the affected one.