🏷️ Basic Information

Make:

BMW

Model:

735iL

Year:

1991

Chassis Code:

E32

Generation:

Second Generation (E32)

👋 Introduction

Market Position:

The 1991 BMW 735iL (E32) represented the pinnacle of luxury and engineering for BMW in its segment, directly competing with Mercedes-Benz S-Class and Lexus LS 400. It was targeted at affluent buyers seeking sophisticated driving dynamics, advanced technology, and uncompromising build quality.

Competitive Analysis:

The E32 7 Series, particularly the long-wheelbase 'iL' variant, offered a blend of executive comfort and driver engagement that set it apart from some competitors. While the Mercedes S-Class often focused more on plush comfort, the BMW 7 Series maintained a reputation for superior handling and a more driver-oriented cockpit. The introduction of the Lexus LS 400 later in the period challenged the segment with exceptional reliability and refinement.

Key Features:

Long wheelbase for enhanced rear passenger space, powerful M30 inline-six engine, advanced (for its time) electronic systems, sophisticated suspension, premium interior materials, and the characteristic BMW driving experience.

📋 Manual Details

Coverage Areas:

Engine, Transmission, Drivetrain, Suspension, Steering, Brakes, Electrical System, Fuel System, Cooling System, HVAC, Bodywork, Diagnostics, Troubleshooting, Maintenance

Page Count:

Estimated 1500+ pages (typical for comprehensive dealer-level service manuals of this era in digital format)

Manual Type:

Official Service and Repair Manual Software

Language:

English

Format:

Software (likely PDF, HTML, or proprietary diagnostic software interface)

📖 Manual Coverage

Systems Covered:

M30B35 Engine, ZF 4HP-22 EH Automatic Transmission, ABS, ASC, Suspension (MacPherson strut front, trailing arm rear), Steering (Hydraulic power steering), Brakes (Vented front discs, solid rear discs), Electrical Distribution System (including fuse box layouts, relay functions), Fuel Injection (Bosch Motronic 3.1), Cooling System, HVAC (Automatic Climate Control), Body Control Modules, Lighting, Safety Systems, On-Board Computer (OBC), Diagnostic Trouble Codes (DTCs)

Procedures Included:

Routine maintenance (oil changes, filter replacements, spark plugs), Engine diagnostics and repair (timing belt, head gasket, fuel injectors), Transmission service and repair (fluid changes, valve body diagnostics), Suspension and steering overhaul, Brake system service (pad/rotor replacement, caliper rebuild), Electrical troubleshooting (wiring diagrams, component testing), HVAC system diagnosis and repair, Body panel repair and adjustment, Pre-delivery inspection (PDI), Torque specifications, Diagnostic procedures using diagnostic tools (e.g., GT1 or similar era tools), Wiring schematics

Technical Depth:

Comprehensive, dealer-level technical information suitable for professional technicians and advanced DIY enthusiasts. Covers basic maintenance to complete engine and transmission rebuilds, electrical system diagnostics, and bodywork.

📊 Manual Specifications

File Format:

Likely PDF with searchable text and high-resolution diagrams. May include interactive elements if part of a larger diagnostic software suite.

Print Quality:

Digital format ensures high-resolution, clear diagrams and text. Printable pages.

Binding Type:

N/A (Digital Software)

Paper Type:

N/A (Digital Software)

⚙️ Engine Specifications

Primary Engine:

3.5L M30B35 Inline-6

Horsepower:

208 hp @ 5,700 rpm

Torque:

225 lb-ft @ 4,000 rpm

Fuel System:

Bosch Motronic 3.1 Electronic Fuel Injection

Engine Layout:

Front-engine, Rear-wheel drive

Bore Stroke:

92 mm x 86 mm

Compression Ratio:

8.0:1

Engine Code:

M30B35

Cooling System:

Pressurized, glycol-based coolant

Ignition System:

Electronic Ignition (Distributorless Coil-on-Plug or Distributor system, depending on specific market/build)

🔧 Transmission

Standard:

ZF 4HP-22 EH 4-Speed Automatic

Optional:

5-Speed Manual (less common on the long-wheelbase iL models)

Features:

Electronic control (EH), Sport/Economy modes

Fluid Type:

ATF Dexron III (or equivalent specified in manual)

📐 Dimensions

Wheelbase:

3070 mm (120.9 in)

Length:

5024 mm (197.8 in)

Width:

1800 mm (70.9 in)

Height:

1400 mm (55.1 in)

Curb Weight:

1800 kg (3968 lbs) approximately

Gross Vehicle Weight Rating:

2270 kg (5005 lbs) approximately

🛡️ Safety Features

Ratings:

No official NHTSA/IIHS ratings for this era. Known for robust construction.

Active Features:

ABS (Anti-lock Braking System), ASC (Automatic Stability Control), Self-leveling rear suspension

Passive Features:

Driver and front passenger airbags (optional/standard depending on market), Crumple zones, Reinforced passenger cell, Seatbelt pre-tensioners

Braking System:

Power-assisted, Anti-lock Brakes (ABS), Ventilated front discs, Solid rear discs

Tire Size:

225/60VR15 (common fitment)

Wheel Bolt Pattern:

5x120 mm

💡 Technology Features

Infotainment:

Cassette player, AM/FM radio, optional CD changer, On-Board Computer (OBC) for trip data, fuel economy, and diagnostics.

Driver Assistance:

ABS, ASC (Automatic Stability Control)

Connectivity:

N/A (No modern Bluetooth or USB connectivity; external phone integration may have been available)

Climate Control:

Automatic Climate Control with dual-zone temperature control

Lighting:

Halogen headlights, fog lights, interior courtesy lighting

🔧 Maintenance

Oil Change Interval:

Every 7,500-10,000 miles or 12 months (depending on driving conditions, refer to manual for specific interval recommendations)

Spark Plug Replacement:

Approx. 30,000 miles (refer to manual for specific spark plug type and interval)

Coolant Flush:

Every 2 years or 30,000 miles

Transmission Fluid Change:

Every 40,000-60,000 miles (recommended, check manual)

Engine Oil Type:

Synthetic 5W-30 or 5W-40 (refer to manual for exact specification, e.g., BMW Longlife-98)

Coolant Type:

Glysantin G05 or equivalent (blue/green coolant) mixed 50/50 with distilled water

Brake Fluid Type:

DOT 4

Known Issues:

Cooling system failures (water pump, radiator, hoses), ABS sensor failures, Headliner sagging, Window regulator issues, Door seal degradation, Fuel distributor or injector leaks, Climate control system malfunctions (blower motor, control head), E32 specific electrical gremlins (e.g., OBC issues, central locking), Self-leveling suspension issues (rear shocks/accumulators)

Oil Filter Part Number:

Mann-Filter W940/2 or equivalent

Air Filter Part Number:

Mann-Filter C27134/2 or equivalent

Cabin Filter Part Number:

N/A (typically not equipped with cabin filter in this generation)

Maintenance Highlights:

Regular inspection and replacement of cooling system components is critical. Monitor for coolant leaks and overheating. Pay attention to the electronic control systems, as they can be complex to diagnose without the proper tools and manual. Regular fluid changes for the transmission are vital for longevity.

📚 Vehicle History

Brand Heritage:

BMW has a long-standing reputation for building performance-oriented luxury vehicles with a focus on driving dynamics and engineering excellence. The '7 Series' designation has always represented the flagship sedan of the brand, embodying its latest technological advancements and commitment to luxury.

Model Evolution:

The E32 generation, launched in 1986, replaced the E23. It was a significant redesign, featuring more aerodynamic styling, a more spacious interior, and the introduction of new technologies like the V12 engine (750iL) and advanced electronic systems. The 735iL was a key model within this lineup, offering a potent inline-six in the long-wheelbase executive sedan package.

Production Years:

1986-1994 (E32 Generation)

Production Location:

Germany

🏆 Awards & Recognition

Recognitions:

While specific awards for the 1991 model year are not readily documented, the E32 generation was widely praised for its engineering, ride comfort, and advanced features, solidifying BMW's position in the luxury sedan market. It was a benchmark for luxury automotive design and technology in its time.