BMW 3-Series Engine Knocking? Here's What Fixed It

Hi there! I had a similar issue with my 2006 BMW 5 series last year. I've got some experience working on cars, but this was beyond my DIY skills. My car showed pretty much the same symptoms, knocking, power loss, and that annoying emergency mode. Turned out it was carbon deposits built up in the combustion chamber. Got it fixed at a workshop, cost me about 425 Euro for a thorough cleaning and service. What's your mileage and maintenance history? Also, have you checked if there are any error codes? This info would help me share more relevant details from my experience. Before you take it in, I'd suggest checking if your car has similar issues to what mine had. The 3 series is actually less prone to this problem than my old 5 series was, but they share similar engine designs.

Hey, thanks for sharing your story! Yeah, my car's at 41673 KM km and just had its service last month. I'm getting those same symptoms, the knocking and power loss are really worrying me. The error codes point to cylinder misfires, but I wanted to hear from others who've dealt with this firsthand. Interesting that carbon buildup was your culprit. That price doesn't sound too bad for peace of mind. Did you notice immediate improvement after the cleaning? My symptoms seem to match yours pretty closely. Think I'll probably need a pro to look at it too.

Hey again! Glad I could help earlier. Yeah, after dealing with those exact issues on my 5 series, I can tell you the improvement after the carbon cleaning was like night and day. The knocking completely disappeared, and the engine felt so much smoother, almost like new. Given your mileage and the cylinder misfire codes, it really does sound similar to what I experienced. The carbon buildup sneaks up on you, even with regular maintenance. In my case, I first tried changing the spark plugs thinking it might be simpler, but that didn't solve it. Just to add something I forgot to mention in my first reply, before getting the cleaning done, my mechanic also checked the fuel injectors since they can contribute to carbon buildup. Turns out they needed a good cleaning too. Might be worth asking about that when you take it in. Trust me, once you get it sorted, you'll notice the difference immediately. My car's been running great for over a year now, no more emergency mode or jerking. Just make sure you find a workshop that knows BMWs well, these engines can be a bit finicky with carbon issues.

Thanks so much for all the detailed info! That's super helpful to know about the fuel injectors too, I'll definitely mention that when I take it in. Really reassuring to hear your car's been running smoothly for over a year after the fix. I've actually got an appointment booked with a BMW specialist workshop for next week. You've made me feel a lot better about this whole situation, at least I know it's probably not something catastrophic. Was getting pretty worried about potential engine replacement costs! Keeping my fingers crossed it's just carbon buildup like yours was. The symptoms match up perfectly, and knowing the cleaning made such a big difference in your case gives me hope. Thanks again for sharing your experience, really helped me understand what I might be dealing with here. Will definitely look into getting those injectors checked while they're at it. Can't wait to get my car running smoothly again. That instant improvement you mentioned sounds amazing right now!