BMW X7 Diesel Jolts and Limps, Owner Seeks DIY Help

Hey there! I faced almost identical issues with my 2017 BMW X5 diesel at around 125K km. The symptoms you're describing are very similar to what I experienced, rough running, limp mode, and that distinct exhaust smell. Got it checked at the garage just two months ago. Turned out the intake manifold had developed cracks due to heat stress, leading to vacuum leaks. The scorching was pretty severe and had damaged the gaskets too. This isn't a minor issue, it affects engine performance significantly and needs immediate attention. In my case, they had to replace the entire intake manifold assembly and gaskets. Also found carbon buildup while they were at it, which needed cleaning. The repair took about two days but solved all those symptoms completely. Based on your description, I'd say you're right about suspecting the intake manifold. It's a known weak point in these engines, especially at higher mileages. Get it checked soon, driving with these symptoms could lead to more expensive damage. Best regards

Thanks for sharing your experience! That's exactly what I was worried about with my X7. Really helpful to know about the intake manifold and carbon buildup issue. By the way, can you remember roughly how much the repairs set you back? Also, has everything been running smoothly since the fix, or have you noticed any other issues popping up? Would really appreciate knowing what I might be looking at cost-wise and if I should expect any other problems down the line. Thanks again for your help!

Hey again! Happy to give you an update! The total bill came to 1180 € for fixing the intake manifold, it was definitely scorched and leaking pretty badly. But I can tell you it was worth every penny because my X5 has been running like a dream since the repair. It's been about two months now, and all those annoying symptoms, the jerking, rough running, and that nasty exhaust smell, they're completely gone. I've put about 5000 km on it since the fix, and honestly, it feels like a different car. The power delivery is smooth again, no more limp mode episodes, and it's back to being the reliable ride I remember. No other issues have cropped up either, which is a relief! Just a heads up though, while they were in there, they recommended regular carbon cleaning maintenance going forward. Apparently, it helps prevent similar issues from developing again. I know it sounds like a lot of money upfront, but considering how much better the car runs now, I'd say it's a solid investment. Let me know if you end up getting yours fixed, would be interested to hear if you have the same positive experience! Best of luck with it!

Thanks for all the detailed info! Just wanted to update you on what happened with my X7. Took it to a mechanic last week and, wouldn't you know it, you were spot on! The intake manifold was completely shot. Got it replaced along with a thorough carbon cleaning. Bill came to around 1300 €, a bit more than yours but not as bad as I'd feared. The difference is like night and day! No more jerking, weird smells, or limp mode. Actually drove it on a long trip yesterday and it performed beautifully. The engine's purring like it's supposed to, and I've got my confidence back in the car. Took your advice about the regular carbon cleaning too, already scheduled my next maintenance. Definitely learned my lesson about keeping up with preventive care. Really appreciate you sharing your experience, saved me a lot of worry and helped me make the right call. Guess we both learned these BMWs need some extra TLC at higher mileage! Thanks again for all your help!

Hello, would a hydrogen cleaning be effective for the intake manifold?

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Hydrogen cleaning can be effective in reducing carbon buildup in the intake manifold and other engine components. It helps improve engine efficiency and performance by cleaning out deposits. However, if there are physical damages like cracks in the manifold, hydrogen cleaning won't fix those issues. It's best used as a preventive maintenance measure rather than a solution for existing mechanical problems. Let me know if you have any further questions!