Segment:
Full-size Luxury Sedan
Positioning:
Flagship model, representing BMW's pinnacle of engineering and luxury for its era.
Primary Competitors:
Mercedes-Benz S-Class (W140), Lexus LS 400, Jaguar XJ, Cadillac Fleetwood
Key Selling Points:
V12 engine, long wheelbase (L designation), advanced technology for the time, superior driving dynamics compared to some rivals, premium materials.
Target Owner:
Discerning buyers seeking performance, luxury, and exclusivity.
Engine:
V12 (M70B50), cylinder head, block, timing, fuel injection, ignition, exhaust
Transmission:
Automatic (e.g., ZF 4HP24), operation, overhaul, diagnosis
Drivetrain:
Rear-wheel drive, driveshaft, differential, axles
Suspension:
Front (double wishbone), Rear (multi-link), springs, dampers, control arms, bushings
Brakes:
Front discs (ventilated), Rear discs, ABS (Anti-lock Braking System), hydraulic system
Steering:
Power-assisted, steering rack, column, linkage
Electrical:
Battery, charging system, starter, lighting, ignition system, onboard computers (DME, ABS, etc.), wiring diagrams
HVAC:
Climate control, A/C system, heater core, blower motor, controls
Bodywork:
Body panels, doors, hinges, latches, glass, seals, interior trim
Comfort Systems:
Power windows, mirrors, seats, sunroof, central locking
Maintenance:
Oil change, filter replacement, fluid checks and changes, spark plug replacement, belt inspection/replacement
Repair:
Engine component replacement (pistons, rods, valves), transmission rebuild, suspension component overhaul, brake caliper replacement, electrical component diagnosis and repair
Diagnostics:
Troubleshooting guides, symptom-based diagnosis, use of diagnostic tools (e.g., OBD-I codes for this era)
Troubleshooting:
System-specific troubleshooting flowcharts and procedures
Adjustments:
Wheel alignment, headlight aiming, idle speed adjustment
Installation:
Component replacement procedures (e.g., replacing starter motor, alternator)
Depth:
Expert level: Covers complete engine and transmission overhauls, detailed electrical diagnostics, and system-specific repairs.
Infotainment System:
BMW Professional RDS radio, cassette player, optional CD changer, integrated navigation system (e.g., BMW Business Navigation).
Driver Assistance Features:
Cruise control, parking sensors (later models/options), electronic climate control.
Connectivity Options:
Limited by era; primarily focused on internal systems and basic telematics if equipped.
Headlight Type:
Halogen or Xenon High-Intensity Discharge (HID) on some models/options.
Oil Change Interval:
Every 7,500 - 10,000 miles or 12 months, whichever comes first (typical for the era, consult manual for precise interval).
Spark Plug Replacement:
100,000 miles (often platinum or iridium tipped, consult manual for exact type and interval).
Coolant Flush:
Every 30,000 - 50,000 miles or 2-3 years.
Engine Oil Type:
BMW High Performance 5W-30 or 5W-40 Synthetic (e.g., Castrol TWS, consult manual for exact spec like BMW Longlife-98 or similar)
Engine Oil Capacity:
Approx. 7.5 Liters (8.0 US Quarts) with filter change.
Coolant Type:
BMW Blue Antifreeze/Coolant (Ethylene Glycol based, 50/50 mix with distilled water)
Common Issues:
V12 engine complexity (e.g., spark plug access, ignition coil issues), cooling system leaks, VANOS seals (if applicable to M70), ABS sensor failures, electronic control unit (ECU) issues, window regulator failures, O2 sensor failures.
Maintenance Considerations:
Due to the complexity of the V12 engine and advanced electronics for its time, specialized knowledge and tools are often required for proper diagnosis and repair.
