Positioning:
The BMW 750iL represented the pinnacle of luxury and performance for BMW in the early 1990s, directly competing with other flagship sedans from Mercedes-Benz (S-Class) and Lexus (LS 400).
Competitors:
Mercedes-Benz W140 S-Class, Lexus LS 400, Jaguar XJ, Rolls-Royce Silver Spirit.
Defining Features:
The V12 engine, long wheelbase, advanced (for its time) electronics, and luxurious interior appointments. The E32 generation was a significant step forward in technology and refinement for BMW's flagship.
Value:
An officially licensed service manual provides the most accurate and complete repair information, essential for maintaining the complex systems of a high-end vehicle like the 750iL, especially for owners and independent specialists.
Powertrain:
Engine (M70 V12), Fuel System, Ignition System, Exhaust System, Cooling System, Lubrication System, Engine Mechanical, Engine Electrical
Drivetrain:
Transmission (4HP24 Automatic), Driveshaft, Differential, Axles
Chassis:
Suspension (Front & Rear), Steering System, Brakes (Hydraulic, ABS), Wheels & Tires
Electrical:
Battery, Charging System, Starting System, Lighting, Instrumentation, Fuses & Relays, Wiring Diagrams, Body Control Modules, Powertrain Control Modules (DME), HVAC Control Modules, ABS Control Modules, OBC (On-Board Computer)
Body:
Body Panels, Doors, Windows, Glass, Locks, Mirrors, Seats, Interior Trim, Exterior Trim, Paint & Corrosion Protection
HVAC:
Air Conditioning, Heating, Ventilation, Climate Control System
Safety Systems:
Seatbelts, Airbags (if equipped, though rare for '91), ABS
Maintenance:
Routine inspections, oil changes, filter replacements, fluid checks and top-offs, spark plug replacement, belt inspections and replacement.
Diagnostics:
Troubleshooting charts, symptom-based diagnostics, fault code interpretation (OBD I era), electrical circuit tracing.
Repair:
Component removal and installation, system overhauls, engine rebuild procedures, transmission repair, brake component replacement, electrical component repair.
Adjustment:
Valve adjustments (if applicable), suspension alignment procedures, idle speed adjustments.
Calibration:
Throttle position sensor calibration, potentially other sensor adjustments.
Wiring:
Detailed electrical wiring diagrams for all systems, troubleshooting guides based on wiring.
Depth:
Comprehensive: Covers everything from basic scheduled maintenance to complex engine, transmission, and electrical system diagnostics and repairs. Suitable for professional technicians and advanced DIY enthusiasts.
Engine Type:
60-degree V12
Displacement:
4.988 liters (304.3 cu in)
Bore X Stroke:
84.0 mm x 90.0 mm (3.31 in x 3.54 in)
Valve Train:
SOHC, 2 valves per cylinder (48 valves total)
Ignition System:
Dual ignition (two spark plugs per cylinder), Distributorless ignition system (DIS) with two ECUs (DME).
Horsepower:
296 bhp (221 kW) at 5200 rpm
Torque:
332 lb-ft (450 Nm) at 3900 rpm
Fuel Delivery:
Bosch Motronic M1.2 (dual ECUs), Multi-point fuel injection (MPI)
Fuel Type:
Unleaded Premium Gasoline (91 Octane or higher recommended)
Coolant Type:
BMW Antifreeze/Coolant (G48, ethylene glycol based, silicate-free).
Oil Type:
SAE 5W-30 or 5W-40 Synthetic Recommended (API SJ/SL or ACEA A3/B3).
Oil Capacity:
Approx. 7.5 liters (7.9 US quarts) with filter change.
Transmission Type:
4-speed Automatic
Transmission Model:
ZF 4HP24
Optional Transmission:
N/A (750iL was exclusively automatic).
Transmission Features:
Electronic control, three shift modes (Economy, Sport, Manual), lock-up torque converter.
Transmission Fluid:
ZF TE-ML 11A/11B or equivalent (e.g., Dexron III H).
Safety Ratings:
Era-specific safety standards. Independent crash test data for this specific model year may be limited or unavailable compared to modern vehicles.
Active Safety:
Anti-lock Braking System (ABS), Power assisted steering.
Passive Safety:
Reinforced passenger cell, front and rear crumple zones, dual-point seatbelts, padded interior surfaces.
Infotainment System:
For its era, it featured a premium sound system, optional CD changer, and an early On-Board Computer (OBC) with basic display functions. Analog climate control. Cassette player standard.
Driver Assistance:
ABS, cruise control, power-adjustable seats with memory, automatic climate control, headlight washers, and often self-leveling suspension. Traction control (ASC) became available on later models or as an option.
Connectivity:
Limited to the car's internal systems. No external connectivity like Bluetooth or USB.
Diagnostic System:
OBD I (On-Board Diagnostics, first generation). Limited self-diagnostic capabilities compared to modern OBD II systems. Requires specialized BMW diagnostic tools of the era for full access.
Oil Change Interval:
Typically every 7,500-10,000 miles (12,000-15,000 km) or annually, using synthetic oil. Check manual for precise intervals based on driving conditions.
Transmission Fluid Change Interval:
Recommended every 30,000-60,000 miles (50,000-100,000 km) or as specified by the service manual. Some sources recommend periodic flushing, others 'lifetime' fluid with filter changes.
Spark Plug Replacement:
Dual ignition; typically around 60,000 miles (100,000 km) or as per manual. Requires 24 spark plugs.
Power Steering Fluid:
ATF Dexron II/III or specific BMW fluid.
Coolant Capacity:
Approx. 12.0 liters (12.7 US quarts)
Common Problems:
Cooling system leaks (especially aluminum radiators and hoses), ABS sensor issues, idle control valve problems, electronic module failures, door seal degradation, headlight leveling system issues, OBC pixelation. The V12 requires meticulous maintenance.
Servicing Complexity:
Due to its complex V12 engine and extensive electronics, the 750iL requires specialized knowledge and tools for proper maintenance and repair.
Heritage:
BMW has a long-standing reputation for building luxurious, performance-oriented automobiles, with the 7 Series serving as their flagship executive sedan since the late 1970s.
E32 Generation:
The E32 generation (1986-1994) replaced the E23 and was a significant technological leap, introducing advanced electronics, improved aerodynamics, and a longer wheelbase option (iL).
Production Period:
1986-1994
M70 Introduction:
The V12 engine (M70) was introduced in 1987 for the 750i and 750iL models, representing BMW's first production V12 engine.
Industry Recognition:
While specific 'awards' for the 1991 model may not be widely publicized in the same way as modern vehicles, the E32 7 Series, and particularly the V12 750iL, was widely recognized for its engineering excellence, luxury, and smooth V12 powertrain.
Design And Engineering:
Consistently praised by automotive journalists for its sophisticated design, robust build quality, and advanced engineering for its time.