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09.09.2024
Due to it's age, the following faults/signs of wear in the roof area of our Z4 E89 will come up:
- Aging batteries suffering from loss of capacity
Car batteries should be replaced after 10 years at the latest, even if the engine still starts. The decreasing capacity of the batteries over the years causes diffuse interference with the electronic control units and can NOT be compensated for by permanent recharging (CETEK etc.).
Replacement: 70Ah, definitely AGM technology! Registering the new battery is necessary to reset the internal statistics.
Nerve factor => Annoying. - Salmon-colored relays
Wearing internal(!) switching contacts on the two salmon-colored relays on the hydraulic pump.
=> No advance warning. This can cause the pump to fail. In rare cases, the hydraulic pump will be destroyed by continuous operation and subsequent overheating. This can happen to anyone who has NOT yet replaced the relays with new ones!
Nerve factor => Drama! - Breakage of sensor wires and hydraulic lines in the rear roof shell
Wire breakage in the rear roof shell in the upper arches that cannot be seen from the outside. In the same place, almost all hydraulic lines have already broken due to material fatigue and will burst at some point.
------- Roof problems, folding roof ------- 
=> Usually no advance warning, Roof movement aborted at any position and no way of return, often no longer possible to close.
There is no emergency operation!
Nerve factor => Drama. - Coupling lock microswitch
Poorly switching coupling lock microswitches on the horizontal hydraulic cylinders in both rear fenders.
=> Advance warning: usually associated with diffuse error situations: sometimes it works, sometimes it doesn't.
Nerve factor => Often Drama, roof doesn't lock. - Hall sensors coupling lock
Hall sensors bursting and corroding in the same place, but only on the right.
=> No advance warning: Roof movement interrupted after opening or closing the vertical trunk lid, less frequently a crash of the main pillar (roof shells) into the still closed trunk lid.
Nerve factor => Drama, possibly Crash of the roof elements.
- Soft Close System in the trunk lid
The moving wires of the microswitches in the trunk locking system on the right and left have broken.
Nerve factor => No warning: the lock no longer locks or is constantly trying to lock.
=> At first it's just annoying because the lock doesn't close and the roof can't be opened. No drama. - Water damage to the hydraulic pump.
- Incorrectly mounted taillights
- Missing sealing of the 3rd hole in the body after replacing a taillight
- Defective rear ventilation flaps
Expensive drama: €3-4,000 - Rear ventilations, 2x partno. 64226909340[/URL][/B]
Replace it each decade, as it becomes weaker and water gets into the trunk. Can be replaced from the inside of the trunk without dismounting the resr bumper.
https://realoem.com/bmw/en/part?id=LM51 ... 4226909340
Have alook at this video:
https://youtu.be/gd1Yyj7TxTs:622 - Gas springs of the trunk lid[/URL][/B]
Get it replaced by new ones:
Stabilus 499514 570N
But, all of thes points can be mitigated with a minimum of efford before it comes to a shutdown!
Just a bit of maintenance will avoid any issue.
How to solve these problems? Have a look at the following maintenance thread:
E89: Retractable Hardtop (roof) Maintenance (and additional) tasksviewtopic.php?p=1861524#p1861524
Update May 2025:
Added 2 additional points, which have become increasingly important in recent years.
. Do you have a preferred charity I can send some money too?