🏷️ Basic Information Identification Make: BMW Model: 520i Year: 1991 Generation Chassis Code: E34 Codes Engine Code Common: M50B20 👋 Introduction Market Position Segment: Executive Sedan Target Audience: Enthusiasts, DIY mechanics, and professional workshops specializing in BMWs. Competitive Analysis Key Competitors Era: Mercedes-Benz W124 E-Class, Audi V8 Quattro, Lexus LS 400 (later in production). Key Features Vehicle Appeal: Renowned for its balanced chassis, refined engineering, and driver-focused experience. Manual Value Proposition: Empowers owners to maintain and repair their classic BMW, preserving its performance and value. 📋 Manual Details Coverage Areas Primary Focus: Full Service and Repair Secondary Focus: Maintenance, Rebuilding, Refurbishment, Restoration, Diagnostics Page Count Estimated Pages: Detailed, likely exceeding 500 pages for comprehensive coverage Manual Type Type: Full Service & Repair Manual Language Language: English Format Format: Likely digital (PDF) given typical modern offerings, potentially available in print. 📖 Manual Coverage Systems Covered Engine: Complete overhaul, internal components, cooling system, lubrication, fuel delivery, ignition, emissions control. Transmission: Manual and Automatic transmission service, repair, and overhaul. Drivetrain: Driveshafts, differentials, axle components. Suspension: Front and rear suspension components, alignment, shock absorbers, springs. Brakes: Hydraulic system, disc brake components (front and rear), parking brake, ABS (if equipped). Steering: Power steering system, steering column, linkages. Electrical: Wiring diagrams, lighting, ignition system, starting and charging, fuse/relay identification, instrument cluster. Body And Chassis: Body panel removal/installation, doors, windows, interior trim, chassis components. Climate Control: HVAC system service and repair. Fuel System: Fuel pump, injectors, fuel lines, evaporative emissions control. Procedures Included Routine Maintenance: Oil changes, filter replacements, fluid checks, belt inspections. Troubleshooting: Systematic diagnostic procedures for common and complex issues. Repair And Rebuild: Step-by-step instructions for component replacement and full rebuilds. Adjustments: Valve adjustments, clutch adjustments, idle speed adjustments. Diagnostics: Engine performance diagnostics, electrical system diagnostics, ABS diagnostics (if applicable). Installation And Replacement: Detailed guides for component installation and replacement. Technical Depth Depth Level: Comprehensive, covering everything from basic checks to complete engine and transmission rebuilds. Diagrams And Illustrations: Extensive use of detailed diagrams, exploded views, and schematics. Torque Specifications: Precise torque values for all critical fasteners. Diagnostic Codes: Information on diagnostic trouble codes (DTCs) and their interpretation, if applicable to E34 generation. 📊 Manual Specifications File Format Digital Format Details: Likely searchable PDF with high-resolution scans of original manual pages. Print Quality Print Quality Description: If printed, expect clear, legible text and high-quality reproductions of diagrams. Binding Type Binding Type Description: If printed, typically coil-bound or perfect-bound for lay-flat use in a workshop. Paper Type Paper Type Description: If printed, often on durable, coated paper suitable for workshop environments. ⚙️ Engine Specifications Primary Engine Engine Type: Inline 6-cylinder, DOHC (Double Overhead Camshaft) Displacement: 2.0 Liters (1991cc) Bore X Stroke: 80.0 mm x 72.0 mm (typical for M50B20) Compression Ratio: 8.8:1 or 9.0:1 (depending on specific variant) Valvetrain: 4 valves per cylinder, DOHC Engine Management: Bosch Motronic (likely Motronic 3.1 or similar) Performance Horsepower Peak: Approx. 150 PS (148 hp; 110 kW) at 6000 rpm Torque Peak: Approx. 190 Nm (140 lb-ft) at 4300 rpm Fuel System Fuel Delivery: Bosch LE-Jetronic or Motronic fuel injection Recommended Fuel: Unleaded gasoline, Octane rating 91 or higher (RON/MON) Emissions Control: Catalytic converter, Lambda sensor (oxygen sensor) 🔧 Transmission Standard Type: Getrag 260 5-speed manual transmission Optional Type: ZF 4HP22 4-speed automatic transmission Features Clutch: Hydraulically actuated single dry plate clutch (manual transmission) Rear Axle Ratio: Typically 3.15:1 or similar, depending on transmission and market. 📐 Dimensions Exterior Length: Approx. 4730 mm (186.2 in) Width: Approx. 1751 mm (68.9 in) Height: Approx. 1412 mm (55.6 in) Wheelbase: Approx. 2760 mm (108.7 in) Weights Curb Weight: Approx. 1450-1550 kg (3197-3417 lbs), depending on equipment 🛡️ Safety Features Ratings Crash Test Data: Limited official crash test data from era, but E34 chassis known for robust construction. Active Features ABS: Anti-lock Braking System (standard on most models, check specific VIN) Traction Control: ASR (Automatic Stability Control) available as an option on some models. Passive Features Airbags: Driver's side airbag typically standard from this year. Seatbelts: 3-point inertia-reel seatbelts front and rear. 💡 Technology Features Infotainment Audio System: Original cassette player with AM/FM radio, optional CD changer integration. Climate Control Type: Manual or optional automatic climate control (ECC - Electronic Climate Control). Driver Assistance Cruise Control: Standard on most models. Connectivity Early Telematics: Limited or no integrated smartphone connectivity; aftermarket solutions are common. 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 7,500-10,000 miles (12,000-16,000 km) or annually, per manual recommendations. Spark Plug Replacement: Around 30,000-60,000 miles (48,000-96,000 km), depending on plug type. Timing Belt Chain: The M50B20 engine features a timing chain, which is designed to last the life of the engine and does not require regular replacement like a belt. However, tensioners and guides can wear. Fluid Specifications Engine Oil Type: API SG, ACEA A2 or A3 specification. Viscosity typically 5W-30,...