Positioning:
The Mercedes-Benz W123 series represented a pinnacle of engineering and build quality in its era, renowned for durability and reliability.
Competitors:
Competed with premium sedans and coupes from brands like BMW (E21, E28), Audi, Volvo, and Jaguar.
Durability:
Exceptional longevity, often exceeding 300,000 miles with proper maintenance.
Build Quality:
Solid construction, robust mechanicals, and a focus on passenger safety.
Diesel Engines:
Introduction of highly successful and durable diesel engines (OM615, OM616, OM617) known for fuel efficiency and longevity.
Model Years Covered:
1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993
Regions Covered:
Global (specifications may vary by market)
Estimated Page Count:
1500+
Type:
Comprehensive Workshop Service and Repair Manual
Engine:
All gasoline and diesel engines (e.g., M110, M115, M116, OM615, OM616, OM617)
Transmission:
Manual and Automatic Transmissions
Fuel System:
Carburetor and Fuel Injection systems (Bosch K-Jetronic, Diesel Injection Pumps)
Electrical System:
Full electrical schematics, lighting, ignition, starting, charging, accessories
Brakes:
Hydraulic systems, discs, drums, ABS (where applicable)
Suspension:
Front and rear suspension, steering system
Body And Chassis:
Body panel repair, structural components, interior trim, glass replacement
Heating And Air Conditioning:
HVAC system operation and repair
Cooling System:
Radiator, water pump, thermostat, fan operation
Maintenance:
Scheduled maintenance, fluid changes, filter replacements, tune-ups
Diagnostics:
Troubleshooting guides, fault finding for engine, electrical, and mechanical issues
Repair:
Detailed step-by-step repair procedures for all major components and systems
Overhaul:
Engine rebuilds, transmission overhauls, differential repairs
Installation:
Component replacement and installation guides
Depth:
Complete workshop level, suitable for professional technicians and advanced DIY enthusiasts
Gasoline Options:
2.0L Inline-4 (M115), 2.3L Inline-4 (M115), 2.5L Inline-5 (M123), 2.8L Inline-6 (M110)
Diesel Options:
2.0L Inline-4 Diesel (OM615), 2.2L Inline-4 Diesel (OM615), 2.4L Inline-4 Diesel (OM616), 3.0L Inline-5 Diesel (OM617), 3.0L Inline-5 Turbo Diesel (OM617)
Horsepower Range:
Approx. 70 hp (OM615 diesel) to 180 hp (M110/M116 variants)
Torque Range:
Approx. 94 lb-ft (OM615 diesel) to 235 lb-ft (OM617 Turbo Diesel)
Gasoline Injection:
Bosch K-Jetronic (CIS) fuel injection on many models
Diesel Injection:
Bosch inline fuel injection pumps
Standard Transmission Types:
4-speed and 5-speed Manual Transmissions
Optional Transmission Types:
3-speed and 4-speed Automatic Transmissions (e.g., 722.1, 722.3)
Automatic Features:
Torque converter, hydraulic control, some models may feature vacuum modulator adjustments.
Wheelbase:
Approx. 107.1 inches (Sedan/Coupe), 112.2 inches (Estate/Long Wheelbase)
Overall Length:
Approx. 187.5 inches (Sedan/Coupe), 195.1 inches (Estate)
Curb Weight:
Approx. 3,100 - 3,700 lbs (depending on body style and engine)
Historic Safety Design:
Designed with a strong emphasis on passive safety, featuring a reinforced passenger cell and crumple zones.
Braking System:
Standard front disc brakes, rear drum brakes. Optional ABS on later models.
Airbags:
Not standard on early models; optional driver airbag available on later production years.
Seatbelts:
Standard three-point front seatbelts, lap belts in the rear.
Audio System:
Factory-provided AM/FM radio, often with cassette player. Aftermarket upgrades common.
Cruise Control:
Optional on many models, typically a vacuum-operated system.
Not Applicable:
No factory-integrated modern connectivity features like Bluetooth or USB.
Oil Change Interval:
Typically every 3,000-5,000 miles or annually, depending on driving conditions and oil type.
Major Service:
Includes spark plugs, fuel filter, air filter, distributor cap/rotor (gasoline), valve adjustments, transmission service.
Engine Oil:
Refer to manual for specific viscosity (e.g., 10W-40, 15W-40) and API service classification based on engine type (gasoline/diesel) and climate.
Transmission Fluid Auto:
MB Spec 236.1 (e.g., Dexron III or equivalent).
Transmission Fluid Manual:
GL-4 gear oil of appropriate viscosity (e.g., 75W-90 or 80W-90).
Coolant:
Ethylene glycol-based antifreeze (e.g., MB Spec 325.0).
Common Wear Items:
Vacuum leaks (lines, actuators), suspension bushings, ball joints, door seals, engine mounts, climate control flap actuators.
Diesel Specific:
Glow plug system, injection pump seals, exhaust manifold cracking (OM617).
Gasoline Specific:
K-Jetronic fuel system complexity, distributor issues, timing chain stretch (M110).
Mercedes Benz Legacy:
Mercedes-Benz has a long history of producing durable, reliable, and technologically advanced vehicles.
W123 Introduction:
Introduced in 1975, the W123 succeeded the W114/W115 ('Stroke Eight') series. The model years covered represent the later half of its production life.
Facelifts:
Key updates during its lifespan included revised interior trim, updated dashboard layouts, and minor exterior styling tweaks.
Production Period:
1975-1986 (Sedan/Coupe), 1977-1985 (Estate), 1978-1985 (Long Wheelbase).
Production Volume:
Over 2.7 million units produced across all body styles, making it one of Mercedes-Benz's most successful models.
