BMW 5 Series Diesel: Rough Idle & Vibration Issues?

Hi there! I've got some experience with BMWs, having owned a 2003 BMW 3 series diesel and currently driving a 5 series too. I had a similar issue last month. The symptoms you're describing sound exactly like what I experienced. After taking it to my mechanic, they found it was actually a loose connection in the engine wiring harness, not the engine mount. The vibrations and rough idle were caused by poor electrical contact. The fix was pretty straightforward, they had to trace and repair some damaged wiring connections. Cost me 95 Euro and the problem hasn't come back since. Could you share which engine variant you have and what specific error codes you're getting? That would help me give you more targeted advice, as these symptoms can sometimes point to different issues depending on the exact model. I'd recommend getting it checked soon though, as electrical issues can sometimes lead to bigger problems if left unchecked.

Thanks for sharing your experience! Mine's at 41684 KM since I got it, and just had its service last month. While I initially thought about engine mounts too, your wiring harness issue got me thinking. Been noticing the vibration gets worse when I'm using electrical components like the AC or radio. After you mentioned the electrical connection problem, that's starting to make more sense now. I'll definitely get those wiring connections checked out first before jumping to more expensive repairs. Really helpful to hear about your real-world fix, makes me hopeful it might be something similarly straightforward! Were there any warning signs before your wiring issue got bad? Just wondering if I should look out for anything specific.

Hey again! Glad my previous reply about the wiring harness helped point you in a possible direction. Actually, yes, now that you mention the vibrations getting worse with electrical components, that's exactly what happened with mine too! Before the wiring issue got really noticeable, I started picking up on small things like slight flickering of the dashboard lights when idling, and the engine would sometimes hesitate for a split second when starting up. Nothing major at first, but these little signs kept getting more obvious. Since you mentioned your car just had service last month, has the vibration started after that? Sometimes these issues can pop up if something wasn't properly reconnected during routine maintenance. In my case, I found out later that some connectors had gotten a bit corroded over time, and the vibration from regular driving just made them progressively looser. One thing I'd suggest, before you take it to the shop, try noting down exactly when the vibrations get worse (like with AC, radio, etc.). This really helped my mechanic pinpoint the problem area faster. My repair was pretty quick once they knew where to look, and saved me from unnecessarily replacing engine mounts. Keep me posted on what you find out. These BMWs can be tricky sometimes, but usually there's a logical explanation for these symptoms!

I appreciate your detailed follow-up about those warning signs! That's definitely useful info about the dashboard lights and startup hesitation, I'll keep an eye out for those. You know what's interesting, now that you mention it, these vibration issues did start pretty soon after the service. I'm thinking you might be onto something about the reconnection issue. I've started keeping a little note on my phone tracking when the vibrations get worse, and it's almost always when I'm running multiple electrical components at once. Feels much better having a clearer direction to investigate instead of just guessing about engine mounts. I've actually scheduled an appointment with my mechanic for next week, and I'll make sure to show them my notes about when the vibrations occur. Really hoping it turns out to be just a wiring issue like yours! Thanks again for taking the time to share all this, it's been super helpful. I'll definitely update once I find out what's actually causing the problem. Fingers crossed it's as straightforward as your fix was!