🏷️ Basic Information Identification Make: Mercedes-Benz Model: 300SE Model Code: W126 Product Name: Mercedes 300SE 1988-1993 Service Repair Workshop Manual 👋 Introduction Market Position Market Segment: Luxury Sedan/Coupe Target Audience: Mercedes-Benz owners, independent repair shops, automotive enthusiasts Competitive Analysis Competitors: BMW 5 Series (E34), Audi V8 Quattro, Lexus LS 400 (from 1989) Key Features Vehicle Selling Points: Build quality, comfort, safety features, refined driving experience, advanced engineering for its time Manual Value Proposition: Enables owners and mechanics to maintain and repair one of Mercedes-Benz's most iconic and durable models, preserving its longevity and performance. 📋 Manual Details Coverage Areas Years Covered: 1988, 1989, 1990, 1991, 1992, 1993 Engine Variants Covered: All 3.0L Inline-6 (M103) variants Chassis Variants Covered: W126 Sedan and Coupe (C126, though primarily focused on Sedan) Page Count Estimated Page Count: 1000+ Manual Type Type: Service Repair Workshop Manual Language Language: English Format Format: Digital (likely PDF) 📖 Manual Coverage Systems Covered Engine Mechanical: Complete overhaul, diagnosis, timing, lubrication, cooling system Engine Electrical: Ignition system (HFM, EZL), fuel injection (Bosch KE-Jetronic variants), starter, alternator Transmission Manual: 4-speed Automatic (722.3, 722.4) overhaul, diagnosis, fluid changes Transmission Automatic: 4-speed Automatic (722.3, 722.4) overhaul, diagnosis, fluid changes Suspension: Front and rear suspension, shock absorbers, springs, control arms, bushings Steering: Power steering system, steering gearbox, tie rods, linkage Brakes: Hydraulic system, ABS (Anti-lock Braking System), brake pads, rotors, calipers, parking brake Electrical System: Wiring diagrams, lighting, power windows, power locks, sunroof, central locking, climate control electronics Body And Frame: Body panels, doors, hood, trunk, interior trim, chassis diagnostics Climate Control: HVAC system, A/C compressor, heater core, blower motor, climate control unit diagnosis Procedures Included Routine Maintenance: Oil changes, filter replacements, fluid checks, tune-ups Engine Repair: Head gasket replacement, piston and ring replacement, valve stem seals, timing chain/belt replacement (if applicable, though M103 is chain driven) Transmission Overhaul: Complete disassembly, inspection, and reassembly of automatic transmissions Brake System Repair: Caliper replacement, brake line bleeding, ABS sensor diagnostics Electrical Troubleshooting: Diagnosing and repairing wiring faults, component testing Suspension And Steering Repair: Ball joint replacement, power steering pump replacement, wheel alignment specifications Technical Depth Depth: Comprehensive: From basic maintenance to complete engine and transmission rebuilds, including advanced diagnostics and component-level repair. 📊 Manual Specifications File Format File Type: PDF Searchability: Searchable text for quick information retrieval Printability: Printable pages Print Quality Quality: High-resolution scans ensuring clarity of diagrams and text Binding Type Binding: N/A (Digital Format) Paper Type Paper Quality: N/A (Digital Format) ⚙️ Engine Specifications Primary Engine Engine Type: M103.980 (300SE) Configuration: 3.0L (2962cc) SOHC Inline-6 Bore X Stroke: 88.0 mm x 80.25 mm Compression Ratio: 9.2:1 Performance Horsepower Net: 189 hp @ 5700 rpm (approx.) Torque Net: 195 lb-ft @ 4400 rpm (approx.) Fuel System Fuel Delivery: Bosch KE-Jetronic (CIS-E) Fuel Injection Fuel Type: Unleaded Premium Unleaded Gasoline (91+ Octane) Fluid Specifications Engine Oil Type: SAE 15W-40 or 10W-30 (API SG or higher) Engine Oil Capacity: 7.0 Liters (7.4 US Quarts) with filter Coolant Type: Mercedes-Benz approved ethylene glycol coolant (e.g., G48) Coolant Capacity: 10.0 Liters (10.6 US Quarts) 🔧 Transmission Standard Type: 4-speed Automatic Model Code: 722.3 or 722.4 Features Shift Modes: Comfort/Economy (E) and Sport (S) modes Fluid Specifications Transmission Fluid Type: MB 236.1 or 236.2 (Dexron II compatible in later years) Transmission Fluid Capacity: 8.0 Liters (8.5 US Quarts) for initial fill 📐 Dimensions Exterior Length: 4,970 mm (195.7 in) Width: 1,790 mm (70.5 in) Height: 1,440 mm (56.7 in) Wheelbase: 2,935 mm (115.6 in) Weights Curb Weight: 1,670 kg (3,682 lbs) Gross Vehicle Weight Rating: 2,160 kg (4,762 lbs) 🛡️ Safety Features Ratings Crash Test Data: While official NHTSA ratings for this era are limited, the W126 was renowned for its robust safety cage and advanced passive safety features for its time. Active Features ABS: Standard Anti-lock Braking System (ABS) Passive Features Airbags: Driver's airbag (standard from 1988 onwards) Seat Belts: Front seat belt pretensioners Construction: Reinforced passenger cell, energy-absorbing crumple zones 💡 Technology Features Infotainment Audio System: Factory premium sound system (e.g., Becker units), often with cassette player Driver Assistance Cruise Control: Standard electronic cruise control Connectivity Phone Integration: Optional early cellular phone integration (rare) Comfort Features Climate Control: Automatic Climate Control (ACC) with cabin air filter Seats: Power adjustable front seats with memory, heated seats (optional) 🔧 Maintenance Service Intervals Oil Change Interval: Every 7,500 - 10,000 miles (or annually) Transmission Fluid Change: Every 30,000 - 40,000 miles (recommended) Coolant Flush: Every 2-3 years or 30,000 miles Spark Plug Replacement: Every 30,000 - 60,000 miles depending on type Known Issues Common Wear Items: Ball joints, tie rod ends, control arm bushings, driveshaft flex discs (guibos), fuel distributor o-rings, idle control valve Electrical Gremlins: Wiring harness degradation (especially around engine bay), vacuum leaks affecting idle and performance, headlight switch issues, window regulator failures. Engine Specific: Head gasket leaks...