Market Position:
The Mercedes-Benz W123 chassis, particularly the 280 CE coupé, represented the pinnacle of luxury, build quality, and engineering in its segment during the late 1970s and early 1980s. It was positioned as a premium grand tourer, blending performance with exceptional comfort and durability, appealing to discerning buyers seeking sophisticated personal transportation.
Competitive Analysis:
Competed against other luxury coupés of the era such as the BMW 6 Series (E24), Jaguar XJ-S, and certain American luxury coupes, offering a distinct combination of German engineering, robust build, and refined styling. The W123 line was renowned for its over-engineered durability, setting it apart from many contemporaries.
Key Features:
Legendary Mercedes-Benz build quality and durability, sophisticated styling, powerful and smooth M110 inline-six engine, comfortable and well-appointed interior, advanced safety features for its time, reliable Bosch K-Jetronic fuel injection, and a reputation for longevity.
Coverage Areas:
Full Service, Repair, Workshop, Maintenance, Diagnostics, Troubleshooting, Electrical Systems, Mechanical Systems, Bodywork
Page Count:
Estimated 1000+ pages (typical for comprehensive factory manuals of this era)
Manual Type:
Factory Service Repair Workshop Manual
Language:
English (likely translated from German factory original)
Format:
PDF (Downloadable)
Systems Covered:
Engine Mechanical (M110), Fuel System (Bosch K-Jetronic), Ignition System, Cooling System, Lubrication System, Exhaust System, Clutch, Manual Transmission, Automatic Transmission (optional), Driveshaft, Differential, Suspension (Front & Rear), Steering System, Brakes (Front & Rear Discs), Electrical System (Wiring Diagrams, Components), Climate Control System, Body & Chassis, Interior Trim, Body Panels, Instrumentation, Exterior Lighting, Interior Lighting, Safety Restraints (Seatbelts)
Procedures Included:
Routine Maintenance (Oil Changes, Fluid Checks, Filter Replacements), Component Removal & Installation, Engine Overhaul, Transmission Rebuilds, Brake System Service, Suspension Component Replacement, Steering System Adjustment, Electrical Troubleshooting, Diagnostic Procedures, Body Panel Repair, HVAC System Servicing, Torque Specifications for all fasteners, Alignment Specifications
Technical Depth:
Comprehensive; covers basic maintenance to complete engine and transmission rebuilds, detailed electrical system diagnostics and wiring diagrams, and specific procedures for component repair and replacement.
Engine Type:
Naturally Aspirated Inline-6
Engine Code:
M110.985 (typically for the 280 CE)
Displacement:
2746 cc (2.75 Liters)
Bore X Stroke:
86.0 mm x 78.7 mm
Compression Ratio:
8.2:1 or 9.0:1 (depending on market and specific variant)
Horsepower Ps:
180 PS (132 kW; 178 hp) at 5,800 rpm (DIN)
Horsepower Hp:
185 hp (138 kW) at 5,800 rpm (SAE net, depending on variant)
Torque Nm:
240 Nm (177 lb-ft) at 4,000 rpm (DIN)
Fuel Injection System:
Bosch K-Jetronic (CIS - Continuous Injection System)
Fuel Type:
Unleaded Gasoline (91 RON / 87 AKI or higher recommended)
Block Material:
Cast Iron
Cylinder Head Material:
Aluminum Alloy
Valvetrain:
Dual Overhead Camshafts (DOHC), 2 valves per cylinder
Standard Transmission:
4-Speed Manual Transmission
Optional Transmission:
4-Speed Automatic Transmission (e.g., 4G-TRONIC)
Transmission Features:
Fluid coupling (automatic), torque converter, hydraulic control (automatic), overdrive gear (in some automatic variants).
Length:
Approximately 4,725 mm (186.0 in)
Width:
Approximately 1,790 mm (70.5 in)
Height:
Approximately 1,420 mm (55.9 in)
Wheelbase:
Approximately 2,795 mm (110.0 in)
Seating Capacity:
5 Passengers
Trunk Volume:
Approximately 0.47 m³ (16.6 cu ft)
Curb Weight:
Approximately 1,450 - 1,550 kg (3,197 - 3,417 lbs), depending on options and transmission
Safety Ratings:
While official crash test ratings from modern agencies are not available for this era, the W123 was renowned for its robust safety cell, crumple zones, and strong chassis construction, considered class-leading for its time.
Active Features:
Four-wheel disc brakes, power-assisted steering, optional ABS (Anti-lock Braking System) on later models.
Passive Features:
Reinforced passenger compartment, energy-absorbing steering column, front and rear crumple zones, laminated windshield, padded interior surfaces, three-point seatbelts (front), dual-circuit braking system.
Infotainment System:
Period-appropriate analog radio, optional cassette player. Focus on build quality and mechanical systems rather than advanced electronics.
Driver Assistance Features:
Power steering, four-wheel disc brakes. Optional cruise control on some models. ABS was introduced on later W123 variants.
Connectivity Features:
None in the modern sense. Connectivity was limited to basic antenna connections for the radio.
Oil Change Interval:
Every 7,500 - 10,000 miles (12,000 - 16,000 km) or 12 months, whichever comes first (check manual for exact specifications based on driving conditions).
Filter Replacement Interval:
Oil filter with every oil change. Air filter and fuel filter typically every 15,000 - 30,000 miles (24,000 - 48,000 km).
Engine Oil Type:
API SG/SH or higher; viscosity typically 10W-40 or 20W-50, depending on climate. Refer to manual for precise grade.
Coolant Type:
Ethylene Glycol based antifreeze/coolant. Mixture ratio 50/50 with distilled water for optimal protection.
Transmission Fluid Manual:
GL-4 gear oil, SAE 75W-90 or 80W-90.
Transmission Fluid Automatic:
Dexron III or equivalent ATF (Automatic Transmission Fluid).
Brake Fluid Type:
DOT 3 or DOT 4.
Known Issues:
Rusting (especially around wheel arches, sills, and jacking points), fuel distributor seal leaks (K-Jetronic), vacuum line degradation, timing chain wear (though generally robust), headlight switch failure, window regulator issues, occasional head gasket leaks (less common than on some other engines of the era).
Engine Oil Capacity W Filter:
Approximately 7.5 Liters (7.9 US Quarts)
Coolant Capacity:
Approximately 9.0 Liters (9.5 US Quarts)
Transmission Fluid Manual Capacity:
Approximately 1.7 Liters (1.8 US Quarts)
Transmission Fluid Automatic Capacity:
Approximately 1.7 Liters (1.8 US Quarts) for pan removal, 8.0-9.0 Liters (8.5-9.5 US Quarts) for complete torque converter refill.
Brand Heritage:
Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and durability, dating back to the invention of the automobile. The W123 cemented this legacy by producing vehicles that became synonymous with reliability and longevity.
Model Evolution:
The W123 series replaced the W114/W115 and was produced from 1976 to 1985. It was available in various body styles including saloon, estate (T-model), coupé, and long-wheelbase versions. The 280 CE represented the sportier, more luxurious coupé variant of the W123 line.
Production Years:
1976-1985
Production Locations:
Germany, South Africa, Austria, Hungary, and other global assembly plants.
Recognitions:
The W123 series as a whole was widely recognized for its exceptional durability and longevity, often cited in automotive publications as one of the most reliable Mercedes-Benz models ever produced. This reliability contributed significantly to Mercedes-Benz's reputation during this era.
Ratings:
Consistently high ratings in customer satisfaction surveys of the time for build quality and reliability. Often praised for its comfortable ride and quiet cabin.
Certifications:
N/A for automotive certifications of this nature in the period. Focus was on meeting rigorous internal Mercedes-Benz engineering and safety standards.
