Finally had a chance to dig into this starting with the partition replacement. BMW unfortunately won't replace any SIB documented issues.

Looks like a corrosion problem, no? That bolt from the rear acoustic cover looks like it came off a 20yr/old vehicle. It was a 5mm socket cap screw.





You guys guessed it, unlucky #5. Obvious from the corrosion!


Design of the partitions are much improved especially the center. It can't leak between the joints due to the co-injected rubber flaps/edges. The material has also changed as you can see from the photo below. They've added a blowing/foaming agent to the plastic but didn't change the thickness. I'm embarrassed to admit that I cracked the right side partition during the install. It as brittle as a potato chip and about as thick as one where it cracked. Added some epoxy and now good as new. Took the SOs watering can and testing the drainage. No leaks in the joints but the left side drains dangerously close to the DDE case.

My outdoor parking situation may have accelerated the corrosion because my driveway in on a 5-7deg incline and I park front down so the rain/melting snow drained forward over the broken partitions. Now I will only park backwards so it only drains out the sides.




I disconnected the electrical connecter on injector #5, sprayed the entire area with WD40 and used compressed air to clear the excess.

After assembling it all, I took it out for about 20 minutes. Once it reached operating temp,I stopped on it a couple times then drove home. It ran perfectly. We'll see how long that lasts. I'm just very relieved that the DDE isn't toast. That's also in an SIB.