🏷️ Basic Information Identification Make: BMW Model: 525i Year: 1981 Codes Chassis Code: E28 Engine Code: M30B25 (2.5L) 👋 Introduction Market Position Vehicle Segment: Executive/Luxury Sedan Target Audience: Affluent individuals seeking performance, comfort, and advanced engineering. Competitive Analysis Key Competitors: Mercedes-Benz W123, Audi 5000, Volvo 240/700 series Key Features Design Philosophy: Driver-focused, engineering excellence, robust build quality, balanced performance. Manual Value Proposition: Essential resource for maintaining and repairing a classic BMW, ensuring longevity and preserving performance. 📋 Manual Details Coverage Areas Manual Type: Service Repair Workshop Manual Language: English Format: Likely printed book (based on description, could be PDF facsimile) Page Count Estimated Page Count: Over 500 pages (typical for comprehensive workshop manuals of this era) 📖 Manual Coverage Systems Covered Engine: Complete overhaul, diagnosis, tuning, fuel injection system (Bosch L-Jetronic), cooling system, lubrication system Transmission: Manual and automatic transmission overhaul, clutch, driveline, propeller shaft, differentials Suspension: Front and rear suspension components, shock absorbers, springs, control arms, bushings, steering system, power steering Brakes: Hydraulic system, brake discs, pads, calipers, master cylinder, power booster, parking brake, ABS (if equipped) Electrical: Complete wiring diagrams, lighting system, starting and charging system, ignition system, fuses, relays, dashboard instruments, power windows, central locking Bodywork: Body panel repair, door mechanisms, window regulators, bumpers, trim, underbody coatings Heating Ventilation Air Conditioning: HVAC system diagnostics, blower motor, heater core, AC compressor and system servicing (if equipped). Procedures Included Maintenance: Routine checks, oil changes, filter replacements, spark plug service, belt adjustments, lubrication points Troubleshooting: Diagnostic charts, symptom analysis, common fault diagnosis for all major systems Repair: Step-by-step overhaul procedures for all major components, component replacement guidelines Technical Specifications: Torque values, clearances, alignments, electrical specifications, fluid capacities and types Drivetrain Repair: Detailed procedures for differential, driveshaft, and axle repairs, including U-joint replacement and axle seal servicing. Chassis Alignment: Wheel alignment specifications and procedures for front and rear suspensions. Technical Depth Depth Of Coverage: Comprehensive, covering from basic maintenance to complete engine and transmission rebuilds. Suitable for professional mechanics and advanced DIY enthusiasts. 📊 Manual Specifications File Format Digital Format Details: If digital (PDF), expect searchable text, high-resolution diagrams, and potentially bookmarking for easy navigation. Print quality of diagrams is crucial. Print Quality Diagram Clarity: High-quality, clear line drawings and exploded views are essential for accurate repair work. Binding Type Binding Style: If printed, likely a durable comb or perfect binding to withstand shop use. Spiral binding is also common for lay-flat usability. Paper Type Paper Quality: If printed, durable, possibly glossy paper for diagrams and coated for resistance to workshop grime. Manual Completeness Coverage Scope: Full factory service manual coverage, providing all necessary information for mechanical and electrical repairs. ⚙️ Engine Specifications Primary Engine Engine Type: Inline-6, naturally aspirated Displacement: 2494 cc (2.5 Liters) Bore X Stroke: 84.0 mm x 75.0 mm Compression Ratio: 8.8:1 (typical) Valve Train: SOHC (Single Overhead Camshaft), 2 valves per cylinder Performance Horsepower: 150 PS (148 hp; 110 kW) at 5500 rpm (approximate) Torque: 215 Nm (159 lb-ft) at 3500 rpm (approximate) Fuel System Fuel Delivery: Bosch L-Jetronic Electronic Fuel Injection Fuel Type: Unleaded Gasoline (Octane rating may vary by region, 91 RON recommended) 🔧 Transmission Standard Type: 4-speed Manual Optional Type: 3-speed or 4-speed ZF Automatic Features Clutch: Single dry plate, hydraulically operated Final Drive Ratio: 3.45:1 (typical, varies with transmission and tire size) 📐 Dimensions Exterior Length: 4620 mm (181.9 in) Width: 1700 mm (66.9 in) Height: 1415 mm (55.7 in) Wheelbase: 2795 mm (110.0 in) Front Track: 1432 mm (56.4 in) Rear Track: 1458 mm (57.4 in) Weights Curb Weight: 1400-1500 kg (approximate, depending on options) Gross Vehicle Weight Rating: 1950 kg (approximate) Cargo Trunk Capacity: 440 Liters (approximate) 🛡️ Safety Features Ratings Crash Safety Standards: Designed to meet 1980s safety standards; lacks modern airbags and advanced crumple zones. Active Features Braking System: Front ventilated discs, rear solid discs. ABS was optional on later models or specific variants, but likely not standard on 1981 525i. Steering: Recirculating ball with power assist Passive Features Seatbelts: 3-point front seatbelts, lap belts in rear Body Construction: Unibody construction with integrated safety cage elements 💡 Technology Features Infotainment Audio System: Factory AM/FM stereo with cassette player, optional premium sound systems. Dashboard: Analog gauges for speedometer, tachometer, fuel, engine temperature, and oil pressure. Check control panel for system status. Driver Assistance Cruise Control: Optional cruise control system. ABS: Anti-lock Braking System was an optional feature on later E28 models, not standard on all 1981 525i variants. Connectivity Connectivity Features: None by modern standards. Basic features like power windows, central locking (optional) were advanced for the time. 🔧 Maintenance Service Intervals Oil Change: Every 7,500-10,000 miles or 12 months (recommendation for modern synthetic oil may differ) Air Filter: Check every 15,000 miles, replace as needed Spark Plugs: Replace every 30,000 miles (Bosch W7DC or equivalent recommended) Coolant Flush:...