Vielleicht ist es wirklich die Steuerkette, die das Heulen bei den E38 12-Zylindern verursacht, wie ojb in Post #67 und Sinclair in Post # 75 vermutet haben.
Ich habe folgenden Post in den USA gefunden:
http://www.bimmerboard.com/forums/posts/68190
Der angesprochene "Service Information Bulletin" hat eine 6-Stellige Nummer (11 06 99), und solche werden zumindest in den USA anscheinend normalerweise für Rückrufe verwendet. BMW Wien hat den Bulletin nicht finden könen. Karl Knauz BMW in den USA (
http://knauzbmw.cms.dealer.com) hat den Bulletin allerdings problemlos aufrufen können. Der Text des Bulletins ist wie folgt:
"BMW SI B 11 06 99
Engine
November 1999
Service Engineering
SUBJECT
Timing Chain Whining Noise
MODEL
E38 750iL with M73 engine (anm.: in den USA gab es den 750i nicht, nur den 750iL)
SITUATION
A whining noise may be heard which is generated by the rotation of the timing chain at approximately 1000 - 1500 rpm at all engine temperatures.
CAUSE
The timing chain noise is a normal engine operating noise which is transmitted to the body of the vehicle and into the passenger compartment via the engine, transmission and exhaust system mounts.
To reduce the amount of transmitted timing chain noise new mounts and engine mount vibration dampers have been developed for the 750iL models with the M73 engines produced up to 8/99. The new mounts were phased into production in 9/99.
Correction
Only if a customer complaint is received regarding a timing chain whining noise at 1000 - 1500 rpm should the engine mounts, transmission mounts and center exhaust mounts be replaced as outlined in the procedure below.
PROCEDURE
Installation of engine mounts, transmission mounts and center exhaust mounts:
- Remove the lower engine splash guard.
- Loosen both left and right side engine mount nuts (right side shown in illustration).
- Remove exhaust system.
- - See repair manual group 18 section 18 00 020.
- Replace center exhaust mounts with new mounts, part number 18 21 1 745 426
- Replace engine mounts with new mounts part numbers: 22 11 1 092 824 (right side) and 22 11 1 092 823 (left side).
- Repair tips: Remove upper section of both air filter housings and center plastic engine cover. Remove radiator fan (see repair manual group 11 section 11 52 020) and the two lower nuts on each engine mount.
- - Carefully raise front of the engine approximately 1 inch (25mm) for appropriate clearance to remove and install the mounts.
- Install new engine mount vibration dampers part number 22 11 6 750 246 on top of the new engine mounts. Tightening torque 31ft.lb. (42Nm.).
- - Note: The new engine mount vibration dampers replace the original engine mount hold down nuts.
- Reinstall upper sections of both air filter housings and the center plastic engine cover.
- Reinstall radiator fan (see repair manual group 11 section 11 52 020). Tightening torque 29.5ft.lb. (40Nm.).
- Support the rear of the transmission and replace the rear transmission mounts with new mounts part number 24 70 1 141 545.
- Reinstall exhaust system.
- - See repair manual group 18 section 18 00 020.
- Reinstall the lower engine splash guard.
PARTS INFORMATION
Part number Description Qty.
18 21 1 745 426 Exhaust mount 2
22 11 1 092 823 Engine mount - Left side 1
22 11 1 092 824 Engine mount - Right side 1
22 11 6 750 246 Engine mount vibration damper 2
24 70 1 141 545 Transmission mounts 2
WARRANTY INFORMATION
Covered under the terms of the BMN New Car Limited Warranty.
Defect Code: 11 31 92 39 00
Labor Operation:
22 11 021: Replace both engine mounts. Includes: Removal and installation of both upper air filter housings, center plastic engine cover and radiator fan. Labor allowance: 17FRU
+ 18 00 520: Removing and installing complete exhaust system. Includes: Replacing both center exhaust mounts. Labor allowance: 10FRU up to 9/98, 12 FRU from 9/98
+ 22 32 500: Replace rear transmission mounts. Labor allowance: 5FRU"
Von einem geplagten Besitzer aus den USA habe ich gehört, daß die Getriebeaufhängungen wahrscheinlich am meisten helfen, dann die Auspuffaufhängungen, und die Motoraufhängungen helfen wahrscheinlich am wenigsten. Ich werde mit BMW Händlern hier in Europa sprechen, wieviel diese Modifikationen kosten. Ich hoffe, sie kosten nicht allzuviel, und daß sie das Heulen beseitigen!