🏷️ Basic Information

Make:

Mercedes-Benz

Model:

300SDL

Year:

1987

Chassis Code:

W124

Engine Code:

OM603.960

👋 Introduction

Market Position:

The Mercedes-Benz 300SDL (W124) represented a significant step in luxury diesel sedans, offering refined comfort, robust engineering, and exceptional fuel economy for its era. It competed with other premium European marques but stood out for its build quality and technological advancements.

Competitive Analysis:

Positioned against models like the BMW 5 Series diesel and Audi V8, the 300SDL emphasized durability, ride comfort, and a quiet cabin, appealing to buyers prioritizing long-term ownership and a smooth, effortless driving experience.

Key Features:

Renowned for its "Tank-like" build quality, sophisticated multi-link rear suspension, and the smooth, torquey OM603 diesel engine. The W124 chassis was a benchmark for its era in terms of engineering and longevity.

Aerodynamics:

The W124 was designed with significant attention to aerodynamics, contributing to its fuel efficiency and reduced wind noise.

📋 Manual Details

Coverage Areas:

Engine, Fuel System, Electrical System, Transmission, Drivetrain, Suspension, Steering, Brakes, Body & Chassis, HVAC, Lubrication, Maintenance, Diagnostics, Troubleshooting, Wiring Diagrams

Page Count:

Estimated 1000+ pages (typical for comprehensive factory-style service manuals)

Manual Type:

Factory Service Manual / Workshop Manual

Manual Scope:

Complete Workshop Manual covering all aspects of vehicle repair and maintenance.

Language:

English

Format:

Digital (likely PDF, potentially searchable)

📖 Manual Coverage

Engine Mechanical:

Complete overhaul procedures, cylinder head, block assembly, crankshaft, pistons, connecting rods, camshaft, valve train, timing chain/belt, lubrication system, cooling system

Engine Management:

Bosch VE Injection Pump, glow plug system, idle speed control, emissions control systems, diagnostic trouble codes (DTCs) if applicable

Fuel System:

Diesel fuel injection system, fuel tank, fuel pump, fuel filter, lines, pressure testing, injector removal/installation

Transmission Manual:

4-speed Automatic Transmission (4G-TRONIC) - overhaul, torque converter, valve body, clutch packs, bands, hydraulic system, shift linkage

Drivetrain:

Driveshaft, universal joints, rear axle differential, axle shafts, wheel bearings

Suspension:

Front and rear suspension components, shock absorbers, springs, control arms, bushings, ball joints, anti-roll bars

Steering:

Power steering system, steering gear, steering column, tie rods, power steering pump, fluid specifications

Brakes:

Front and rear disc brakes, brake calipers, rotors, pads, master cylinder, brake booster, ABS (Anti-lock Braking System) diagnosis and repair, parking brake

Electrical System:

Battery, alternator, starter motor, ignition system (glow plugs), lighting system, fuses, relays, power windows, central locking, instrument cluster, diagnostic connectors

HVAC:

Air conditioning system diagnosis and repair, heater core, blower motor, climate control unit, refrigerant handling (refer to specific refrigerant and safety guidelines)

Body Chassis:

Body panel removal/installation, door mechanisms, window regulators, seat adjustments, interior trim, exterior trim, structural components

Emissions Control:

Details on emissions control systems relevant to the 1987 diesel regulations, including components and basic troubleshooting.

Tire Wheel:

Tire pressure recommendations, wheel torque specifications, and typical wheel/tire sizes for the model.

Maintenance:

Scheduled maintenance, oil changes, filter replacements, fluid checks and top-offs, belt inspection and replacement, spark plug replacement (if applicable for starting system), chassis lubrication

Diagnostics:

Systematic troubleshooting guides, diagnostic flowcharts, component testing procedures, identification of common faults

Component Overhaul:

Overhaul procedures for major components (engine, transmission, differential)

Component Replacement:

Component removal, installation, and adjustment

Electrical Troubleshooting:

Wiring diagram interpretation and tracing

Torque Specifications:

Torque specifications for critical fasteners

Diagnostic Trouble Codes:

Procedures for reading and interpreting diagnostic codes if present for specific electronic modules (e.g., ABS).

Alignment Specs:

Wheel alignment specifications (camber, caster, toe) for front and rear suspensions.

HVAC Recharge Procedures:

While not a DIY task due to refrigerant handling, the manual would detail system components, pressure checks, and component replacement. Specific refrigerant type (R12 for this era) and safety protocols are crucial.

Technical Depth:

Comprehensive, covering everything from basic scheduled maintenance to complete engine and transmission rebuilds. Includes detailed diagnostic procedures and specifications for professional technicians.

Wiring Diagrams Detail:

Comprehensive, color-coded wiring diagrams for all major electrical systems, facilitating diagnosis of electrical faults.

📊 Manual Specifications

File Format:

Likely PDF. High-resolution scans for clarity, potentially with searchable text. Embedded bookmarks for easy navigation.

Print Quality:

Excellent, clear diagrams and text suitable for printing individual pages or sections as needed.

Binding Type:

N/A (Digital Format)

Paper Type:

N/A (Digital Format)

⚙️ Engine Specifications

Engine Type:

Inline 6-Cylinder, Naturally Aspirated Diesel

Displacement:

2,996 cc (3.0 Liters)

Bore X Stroke:

87.0 mm x 84.0 mm

Compression Ratio:

22.0:1

Horsepower Net:

109 hp @ 4,600 rpm

Torque Net:

195 lb-ft (265 Nm) @ 2,400 rpm

Fuel Injection:

Bosch VE (Variable) Rotary Injection Pump

Fuel Type:

Diesel

Glow Plug System:

Pre-glow and post-glow system for reliable cold starts

Oil Capacity:

7.5 Liters (8.0 US Quarts) with filter

Recommended Oil Viscosity:

API CD or CE, SAE 15W-40 or 10W-40 (depending on climate)

🔧 Transmission

Transmission Type:

4-Speed Automatic (4G-TRONIC)

Optional Transmission:

Not available for 300SDL model year 1987

Transmission Features:

Lock-up torque converter, electronically controlled shifts (for its time), comfort-oriented shift points.

Transmission Fluid Type:

MB Spec 236.1 (e.g., Dexron II)

Transmission Fluid Capacity:

Approximately 8.0 Liters (refer to manual for exact fill procedures)

📐 Dimensions

Length:

4740 mm (186.6 in)

Width:

1740 mm (68.5 in)

Height:

1430 mm (56.3 in)

Wheelbase:

2795 mm (110.0 in)

Curb Weight:

1650 kg (3638 lbs)

Gross Vehicle Weight Rating:

2100 kg (4630 lbs)

Trunk Capacity:

Approximately 520 Liters (18.4 cu ft)

🛡️ Safety Features

Safety Ratings:

Specific NHTSA/Euro NCAP ratings for this model/year are not readily available from modern databases, but the W124 chassis was known for its robust safety cage and energy-absorbing crumple zones, setting high standards for its time.

Active Safety:

Anti-lock Braking System (ABS), Power assisted steering

Passive Safety:

Reinforced safety cell, impact-absorbing steering column, driver's side airbag (optional on some early W124s, standard on later models, likely optional for 1987 300SDL), three-point seatbelts with front pre-tensioners

💡 Technology Features

Infotainment System:

Basic analog radio with cassette player. Optional enhancements like power antenna and upgraded speaker systems were available.

Driver Assistance Features:

ABS (Anti-lock Braking System) was a significant feature for the era. Cruise control was also commonly equipped.

Connectivity Features:

No modern connectivity features like Bluetooth or USB. Analog systems.

🔧 Maintenance

Oil Change Interval:

Every 7,500 miles or 12,000 km, or annually, whichever comes first.

Fuel Filter Replacement:

Every 15,000 miles or 24,000 km, or annually.

Air Filter Replacement:

Every 15,000 miles or 24,000 km, or as needed based on inspection.

Transmission Fluid Change:

Every 30,000 miles or 48,000 km, or every 2 years.

Coolant Flush:

Every 2 years or 50,000 km (80,000 miles).

Engine Coolant:

MB Spec 325.0 (Ethylene Glycol based, typically a 50/50 mix with distilled water)

Brake Fluid:

DOT 4

Power Steering Fluid:

MB Spec 236.3 (ATF or specific power steering fluid)

Known Issues:

Heated windshield wiper parking position (can crack paint), rust in common areas (wheel arches, underbody), vacuum line leaks affecting central locking and climate control, power seat module failures, timing chain tensioner wear (though OM603 is generally robust), injector seal leaks.

Common Repairs:

Replacement of vacuum hoses, HVAC blower motor resistor, ABS sensors, suspension bushings, and addressing rust points.

📚 Vehicle History

Brand Heritage:

Mercedes-Benz has a long-standing reputation for engineering excellence, luxury, and durability, dating back to the invention of the automobile. The W124 generation continued this legacy with a focus on advanced technology and build quality.

Model Evolution:

The 300SDL is part of the W124 E-Class generation, which succeeded the W123. It introduced significant advancements in chassis design, suspension, and engine technology. The 'SDL' designation indicated the long-wheelbase version with the diesel engine.

Production Years:

W124 E-Class: 1984/1985 - 1995/1996. The 300SDL variant was produced approximately from 1986 to 1991.

Manufacturing Locations:

Germany (primarily Sindelfingen and Bremen)

🏆 Awards & Recognition

Recognitions:

The W124 generation consistently received critical acclaim for its build quality, durability, and engineering. While specific awards for the 1987 300SDL may not be cataloged, the model series was widely regarded as a benchmark for luxury sedans in the 1980s and early 1990s.