All of the other o-rings and seals on the top of the engine, such as VANOS solenoid o-rings, camshaft position sensor o-rings, eccentric shaft sensor sealing elements, valvetronic actuator sealing elements and o-rings, vacuum pump o-ring, spark plug tubes, oil pressure switch, etc.


You're doing the lower timing case covers? Are they leaking? That seems like a very big job. If you're really going in that far, then inspect and clean the tensioners, and inspect or replace the guides. I haven't heard of a need to replace the guides like in other BMW engines where they break sometimes.