🏷️ Basic Information Identification Make: BMW Model: 3 Series Chassis Code: E21 Production Years Covered: 1975-1983 👋 Introduction Market Position Target Audience: BMW E21 owners, DIY enthusiasts, independent repair shops Competitive Analysis Differentiation: Make, model, and year specific, not generic; comprehensive coverage from basic maintenance to engine rebuilds. Key Features Key Features: Instant download, detailed diagrams, comprehensive system coverage, troubleshooting guide. 📋 Manual Details Coverage Areas Coverage Scope: Comprehensive workshop repair, maintenance, and troubleshooting Body And Trim: Includes information on body panel removal, repair, and adjustment, as well as interior trim components. Page Count Estimated Page Count: Not specified, but implied to be extensive given the scope. Manual Type Type: Service and Repair Manual Language Language: English Format Format: PDF 📖 Manual Coverage Systems Covered Engine Systems: Engine removal/installation, cylinder head/valve, cylinder/piston, crankcase, crankshaft/primary shaft, fuel system, lubrication Drivetrain Systems: Clutch, gearshift linkage, sub-transmission, transmission Suspension Steering: Front wheel/suspension, rear wheel/suspension Braking Systems: Hydraulic brake system Electrical Systems: Battery/charging system, ignition system, electric starter, switches, re-wiring Procedures Included Maintenance: Inspection and adjustment, lubrication, fluid capacities Repair: Engine rebuilding, component repair, system overhauls Diagnostics: Troubleshooting Engine Rebuild: Detailed procedures for valve lapping, piston ring replacement, bearing replacement, timing chain/belt adjustments, and more. Electrical Diagrams: Comprehensive electrical schematics for all major vehicle systems, crucial for troubleshooting and repairs. Fuel System Repair: Carburetor overhaul and adjustment, fuel pump testing, fuel injector cleaning and replacement (for fuel-injected models). Ignition System Repair: Distributor maintenance, ignition coil testing, spark plug replacement, timing adjustments. Technical Depth Depth: Detailed step-by-step instructions with diagrams for workshop-level repairs. Special Tools: Implies the need for specific BMW special tools for certain repair procedures, which would be detailed in the manual. Troubleshooting Approach: Systematic approach to diagnosing faults with symptom-based guidance. 📊 Manual Specifications File Format Compatibility: PC/MAC compatible Usability: Printable pages or viewable on screen, zoom in/out capability Delivery Method: Instant Download via email link Print Quality Quality: High quality, easy to follow detailed instructions and step-by-step diagrams Binding Type Binding: N/A (Digital PDF) Paper Type Paper Type: N/A (Digital PDF) ⚙️ Engine Specifications Primary Engine Engine Variants Covered: Likely covers the M10 4-cylinder engines (e.g., 316, 318, 320) and potentially the M20 6-cylinder engines (e.g., 320i, 323i) depending on specific manual content within the range. Performance Typical Performance Range: Horsepower ranged from approximately 90 hp for early 4-cylinder models to around 143 hp for the 323i. Fuel System Fuel Delivery: Carburetor (Solex, Zenith) for base models, Bosch L-Jetronic or K-Jetronic fuel injection for performance models. Engine Layout Layout: Inline 4-cylinder (M10) and Inline 6-cylinder (M20) Cooling System Type: Liquid-cooled Cylinder Head Head Design: SOHC (Single Overhead Camshaft) Engine Identification Engine Codes: M10 (e.g., M10B18, M10B20) and M20 (e.g., M20B20, M20B23) 🔧 Transmission Standard Transmission Types: 4-speed manual, 5-speed manual (later models), 3-speed automatic Optional Optional Transmissions: 5-speed manual, automatic transmission Features Clutch Type: Single dry plate diaphragm spring clutch Driveshaft: Open driveshaft to rear differential 📐 Dimensions Exterior Body Styles: 2-door sedan (coupe styling), 4-door sedan Wheelbase: Approx. 2570 mm (101.2 in) Weights Curb Weight Range: Approx. 1100-1300 kg (2425-2866 lbs) Gross Vehicle Weight Rating: Varies by model and configuration, typically around 1600-1700 kg 🛡️ Safety Features Ratings Crash Test History: NHTSA and IIHS ratings from this era are limited; emphasis was on passive safety features of the time. Active Features Active Safety: Four-wheel disc brakes (standard on most models), independent suspension. Passive Features Passive Safety: Reinforced passenger cell, collapsible steering column, padded dashboard. Braking System Brake Type: Front: Ventilated discs; Rear: Discs (or drums on very early base models) 💡 Technology Features Infotainment Audio Systems: Optional period-correct radio/cassette players. Basic sound systems. Driver Assistance Driver Aids: None by modern standards. Focus was on mechanical feedback and driver control. Lighting Headlights: Halogen headlights were standard or optional depending on market and trim. 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 5,000-10,000 km (3,000-6,000 miles) or annually, depending on driving conditions. Manual will specify exact intervals. Tune Up Interval: Spark plugs, ignition timing, and carb/injection adjustment typically recommended every 20,000-40,000 km (12,000-24,000 miles). Fluid Specifications Engine Oil: Refer to manual for specific API ratings (e.g., SE, SF) and viscosity grades (e.g., 10W-40, 20W-50) based on climate. Coolant: Ethylene glycol based antifreeze with a 50/50 mix with distilled water. Transmission Fluid: Manual: GL-4 rated gear oil (e.g., SAE 75W-90 or 80W-90). Automatic: DEXRON-II or equivalent. Brake Fluid: DOT 3 or DOT 4 (check manual for specific recommendation) Differential Fluid: GL-5 rated gear oil (e.g., SAE 75W-90 or 80W-90), specific viscosity may vary based on limited-slip differential if equipped. Known Issues Common Problems: Rust (especially wheel arches, sills, strut towers), worn front suspension bushings, aging rubber hoses and seals, fuel leaks from carburetors or injection systems, ignition system component failures (points, condenser, coil), differential pinion seal leaks. Electrical Quirks: Corroded wiring connectors,...