BMW 6 Diesel Issues: Timing System Problem or Something Else?

Hi there! I have some experience working on cars, and I dealt with very similar issues on my 2003 BMW 5 Series diesel (had a few BMWs, including a 3 Series). The symptoms you're describing sound exactly like what I experienced. It turned out to be a faulty crankshaft position sensor in my case. Had it diagnosed and fixed at my regular workshop, cost me around 340 Euro all in. The repair wasn't too complex, but it needed specialized diagnostic equipment. The metallic noise during cold starts, combined with the power loss and increased fuel consumption, are typical signs of this issue. The engine management system gets confused without proper crankshaft position data. Could you share more details about your car? Like the exact engine code and mileage? This would help confirm if we're looking at the same problem. Also, are you getting any specific error codes?

Thanks for sharing your experience! My engine code is the N57 and I'm currently at 194,491 KM. Had my last service about 3 months ago. What's interesting is that my mechanic actually thought it might be the crankshaft sensor too, but wanted to run more tests. The symptoms do match up exactly with what you described. Was your metallic noise also more noticeable first thing in the morning? And did you notice any hesitation when accelerating before you got it fixed? Just wondering, how long did the repair take at your workshop? I need to plan around work schedules if it's the same issue.

Hi again! Yes, I had exactly the same experience with my BMW. The metallic noise was definitely worst in the mornings, especially during winter. And yes, there was a noticeable hesitation when accelerating, it felt like the car was constantly second-guessing itself. The repair at my workshop took about 4-5 hours total. They needed some time to run diagnostics first to be absolutely certain it was the crankshaft sensor, then the actual replacement was pretty straightforward. I'd suggest blocking out a full day just to be safe, though. With your mileage being similar to what mine was when I had the issue (I was at around 188,000 KM), and having the same engine code, I'm even more convinced it's the same problem. After they replaced my sensor, all those issues disappeared completely, no more metallic noise, power came back to normal, and fuel consumption dropped back to what it should be. Just a heads up, make sure they check the wiring harness too while they're at it. In my case, there was some minor wear on the wires leading to the sensor that they fixed while they were in there. Might save you another trip to the shop down the road.

Really appreciate all the detailed info! That's super helpful, especially about checking the wiring harness, definitely gonna mention that to my mechanic. Actually feeling a bit relieved now knowing it might just be the crankshaft sensor rather than something more serious. I'll go ahead and schedule it for next week and block out the whole day like you suggested. It's good to know the repair time isn't too long. The symptoms match up so perfectly with what you experienced, especially that morning noise and acceleration hesitation. Plus, our cars being at similar mileage when the problem showed up makes me pretty confident this is what I'm dealing with. Thanks again for taking the time to share your experience. You've saved me a lot of worry, and probably some money too by helping me narrow down the problem before heading to the shop.