BMW 3 Diesel Problems: Multiple Symptoms Point to Crisis

Hey there! I've got some experience working on cars and went through something very similar with my 2020 BMW 520d. I had almost identical problems, rough running, jerking, and that distinctive diesel smell. After limping to my trusted workshop, they diagnosed a scorched intake manifold that was causing air leaks. The repair bill came to 1180 Euro, not cheap, but it fixed everything. The car's been running perfectly since then, about 8 months now. Before jumping to conclusions though, any specific error codes you're getting? When did these symptoms first appear? Does it get worse when the engine's hot or cold? These details would help confirm if you're dealing with the same issue I had. Give me that info, and I can share more specifics about my repair experience.

Thanks for sharing your experience! My issue sounds really similar to what you described. Just had my service at 190149 KM and everything was perfect then, but these symptoms started showing up suddenly last week. Getting error codes P0299 and P0401, and yeah, it definitely gets worse when the engine's warm. The diesel smell is particularly strong when accelerating, and the jerking is most noticeable between 1500-2500 RPM. It's reassuring to hear you got yours sorted with an intake manifold replacement. I'll probably get it checked at the workshop this week, though I'm not looking forward to that repair bill! At least now I have a better idea of what to expect. Did your car also make any unusual whistling sounds before you got it fixed? Just noticed that happening with mine too.

Hey again! Yeah, now that you mention the whistling sound, I definitely had that too with my 520d! It's actually one of those telltale signs I forgot to mention in my first reply. That whistling noise was most noticeable for me just before everything went downhill. Looking at your error codes and symptoms, it's even more certain we had the same issue. P0299 and P0401 were exactly what my car was throwing too. The way you describe the jerking between 1500-2500 RPM is spot on, that's precisely how mine behaved. Just a heads up though, when I got mine fixed, they also found some carbon buildup that had contributed to the problem. My mechanic recommended doing a carbon cleaning while they had everything apart, which added about 200 to the bill but was worth it in the long run. Might be worth considering since you're at 190k km. One thing I learned from my experience, don't wait too long to get it fixed. I tried pushing through it for a week or so, and it just got worse. Plus, you risk damaging other components if you keep driving it in this condition. Let me know how it goes when you get it checked out. I'm curious if it turns out to be the same exact issue as mine!

Thanks a lot for all this detailed info! That's super helpful to know about the carbon buildup too, definitely something I'll discuss with my mechanic. You're probably right about not waiting too long to get it fixed. After hearing about your experience, I've actually called the workshop and booked it in for tomorrow morning. The fact that you had the exact same error codes and symptoms really puts my mind at ease, at least I know what I'm likely dealing with now. I'll go ahead and mentally prepare for that hefty repair bill, but honestly, it's better than letting it get worse and potentially causing more damage. I appreciate you taking the time to share your experience in such detail. Will definitely get that carbon cleaning done while they're at it. I'll let you know how it turns out, but I'm pretty confident now that we're looking at the same issue. Thanks again for all your help!