BMW X6 Stalling & Hissing: Multiple Symptoms Point to Leak

Hey there! I had nearly identical issues with my 2015 BMW X5 35i last winter. The symptoms you're describing match what I experienced, the hissing, jerking, and terrible fuel economy. Turned out my intake boot had several small cracks and one major tear, causing a significant vacuum leak. Got it fixed at the garage, they had to replace the intake boot, some clamps, and checked all connecting hoses. It wasn't a complex repair, but definitely not something you want to leave unattended as it can cause long-term engine damage and performance issues. Since the repair, my X5 has been running smooth, no more hissing, stalling, or check engine lights. Fuel consumption went back to normal too. Would definitely recommend getting this checked soon, especially with those emission test failures. Interesting thing, the mechanic showed me how rubber components in these engines tend to deteriorate over time due to heat cycles. Common issue in our BMW engines, apparently. Hope this helps with your decision.

Thanks for sharing your experience! Really glad to hear you got your X5 sorted out. Since you had such a similar issue, do you remember roughly how much the repair set you back? And has everything stayed running smoothly since then, or have you noticed any other quirks popping up? I've been putting off getting mine fixed because I was worried about getting ripped off, but hearing your success story is giving me more confidence to just get it done. Thanks again for the detailed info!

Hey again! Absolutely happy to share, after getting my X5 fixed, it's been running like a dream! The repair was actually pretty reasonable, paid 100 € for replacing the leaking intake hose. Money well spent, if you ask me! Since having it sorted at the mechanic, all those annoying problems disappeared completely. No more hissing sounds, the jerky acceleration is gone, and my fuel consumption is back to what it should be. It's been several months now, and I haven't had a single issue pop up. I totally get being worried about repair costs, I was in the same boat! But honestly, fixing an air intake leak is pretty straightforward work, and most shops won't charge you an arm and a leg for it. The sooner you get it done, the better it is for your engine in the long run. If you're still unsure, I'd say just go for it. The peace of mind alone is worth it, and your X6 will thank you for it! Let me know how it goes if you get it fixed!

Thanks so much for all the helpful info! Just wanted to update you, I finally took your advice and got my X6 checked out yesterday. You were spot on about everything! The mechanic found multiple cracks in the intake boot, just like you mentioned. Ended up paying about 120 € for the whole fix, which honestly wasn't as bad as I'd feared. Got to watch them do the repair too, pretty interesting to see how these things work. The difference is like night and day! No more hissing, the engine's running smooth as silk, and that annoying jerking is completely gone. Should've done this weeks ago instead of worrying about it. Feels great to have my car back to normal, and my wallet didn't take too big of a hit either. Really appreciate you sharing your experience, it gave me the push I needed to get this sorted. Now I can finally enjoy driving again without stressing about every little noise!