🏷️ Basic Information Identification Make: Infiniti Model: Q45 Year: 1991 👋 Introduction Market Position Positioning: The 1991 Infiniti Q45 was positioned as a luxury flagship sedan, directly competing with established European and American luxury marques, emphasizing performance and a unique, bold design. Competitive Analysis Competitors: Mercedes-Benz S-Class, BMW 7 Series, Lexus LS 400, Cadillac DeVille, Lincoln Town Car. Key Features Features: Powerful V8 engine, advanced suspension (multi-link front and rear), luxurious interior appointments, distinctive exterior styling. Driving Dynamics: Renowned for its refined ride and confident handling, a departure from many traditional American luxury cars of the era. 📋 Manual Details Coverage Areas Coverage: Comprehensive service and repair information for the 1991 Infiniti Q45. Page Count Page Count Estimate: Likely extensive, typical for OE service manuals (e.g., 1000+ pages, not specified in product info). Manual Type Type: Official Service and Repair Manual Software Licensing: Officially licensed, derived from OE (Original Equipment) materials. Language Language: English Format Format: Online software/web-based access 📖 Manual Coverage Systems Covered Systems: Engine, Drivetrain, Suspension, Steering, Brakes, Electrical Systems, HVAC, Body, Chassis, Fuel System, Exhaust System, Cooling System, Lubrication System, Ignition System, Emission Control System. Electrical Systems: Comprehensive coverage including engine control, lighting, power accessories, dashboard instrumentation, audio system, HVAC controls, and ABS system wiring diagrams. Drivetrain: Rear-wheel drive system, driveshafts, differential, axles. Brakes: Front and rear disc brakes, hydraulic system, ABS component details. Steering: Power assisted rack and pinion steering, steering column components, tie rods, linkages. HVAC: Air conditioning system (refrigerant type, components, service), heater system, climate control unit operation and repair. Procedures Included Procedures: Routine maintenance, diagnostics, troubleshooting, component replacement, repair procedures, assembly/disassembly, electrical wiring diagrams, torque specifications, special tools, and procedures. Troubleshooting: Detailed diagnostic flowcharts, symptom-based troubleshooting guides, and component testing procedures. Maintenance: Scheduled maintenance intervals, fluid checks and changes, filter replacements, inspection points. Repair: Detailed step-by-step repair instructions for all major and minor components. Technical Depth Depth: Factory-level detail suitable for professional technicians and advanced DIYers, covering everything from basic fluid changes to complete engine and transmission rebuilds. Diagnostics: Includes information on the OBD-I diagnostic system (or Nissan's proprietary diagnostic port) and codes relevant to the 1991 model year. 📊 Manual Specifications File Format Format: Web-browser accessible software, likely HTML5/JavaScript based. Accessibility: Accessible on PC, laptop, smartphone, or tablet with an internet connection and web browser. Print Quality Print Quality: N/A (Digital Format), but derived from OE materials implying high-quality technical illustrations and diagrams. Binding Type Binding: N/A (Digital Format) Paper Type Paper Type: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Code: VH45DE Engine Type: 4.5L DOHC 32-valve V8 Performance Horsepower: 278 hp @ 6000 rpm (approximate) Torque: 297 lb-ft @ 4000 rpm (approximate) Fuel System Fuel Delivery: Electronic Fuel Injection (EFI) with multi-port injection. Recommended Octane: Premium Unleaded Gasoline (91 Octane or higher) Cooling System Coolant Capacity: Approximately 10.6 quarts (10.0 liters) - refer to manual for exact specification. Lubrication Oil Capacity: Approximately 5.3 quarts (5.0 liters) with filter change - refer to manual for exact specification. Recommended Oil Viscosity: 5W-30 or 10W-30 API SG/SH - refer to manual for exact specification. Engine Type Engine Block Material: Aluminum Alloy Cylinder Head Material: Aluminum Alloy 🔧 Transmission Standard Transmission Type: 4-speed Automatic Transmission Model: RE4R01A Features Shift Modes: Normal and Sport modes. Fluid Type Transmission Fluid: Dexron III/Mercon (refer to manual for exact specification and part number). 📐 Dimensions Exterior Length: 198.0 inches (5029 mm) Width: 71.7 inches (1821 mm) Height: 55.7 inches (1415 mm) Wheelbase: 113.2 inches (2875 mm) Weights Curb Weight: Approximately 4000-4200 lbs (1814-1905 kg) depending on options. 🛡️ Safety Features Ratings NHTSA Front Impact: Not rated (NHTSA ratings were less standardized in 1991). Active Features ABS: Standard Anti-lock Braking System (ABS). Passive Features Airbags: Driver's side airbag standard. Seatbelts: Three-point inertia-reel seat belts for all occupants. 💡 Technology Features Infotainment Audio System: Premium Bose audio system was often standard or optional, featuring CD player and cassette deck. Climate Control: Automatic climate control with digital display. Driver Assistance Cruise Control: Standard electronic cruise control. Suspension Features: Active Suspension System (optional on some models/trims) for enhanced ride and handling control. This manual would detail its operation and service. Connectivity Connectivity Features: Limited by 1991 standards; primarily focused on internal vehicle systems and premium audio. 🔧 Maintenance Service Intervals Oil Change Interval: Every 3,750 miles or 6 months (refer to manual for specific conditions and extended intervals). Spark Plug Replacement: Approximately 60,000 miles (refer to manual for specific plug type and torque). Timing Belt Replacement: The VH45DE engine uses a timing chain, not a belt, eliminating this regular replacement interval. Fluid Specifications Brake Fluid: DOT 3 or DOT 4 (refer to manual for exact specification and part number). Power Steering Fluid: Nissan/Infiniti Genuine Power Steering Fluid or equivalent (refer to manual for exact specification and part number). Known Issues Common...