Segment:
Mid-size luxury sedan and coupe
Target Audience:
Affluent buyers seeking comfort, safety, and engineering excellence.
Competitors:
BMW 5 Series (E12/E28), Audi 100, Volvo 240/260 series, Jaguar XJ.
Design Philosophy:
Robust build quality, exceptional durability, advanced engineering for its era, focus on passive safety.
Reputation:
Known for its legendary longevity, build quality, and ability to rack up high mileage with proper maintenance.
Covered Models:
Mercedes-Benz W123 280SE
Covered Years:
1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985
Type:
Workshop Service Repair Manual
Engine:
Comprehensive engine repair, overhaul, tuning, lubrication system, cooling system, fuel system, ignition system
Transmission:
Repair and overhaul procedures for automatic and manual transmissions
Electrical:
Detailed electrical system diagrams, troubleshooting, repair of lighting, ignition, starting, charging, and accessories
Bodywork:
Body repair, panel replacement, interior trim, glass, doors, and windows
Chassis:
Suspension, steering, brakes, wheels, and tires
Fuel System:
Fuel injection system (Bosch K-Jetronic for 280SE), fuel pump, lines, filter, and tank
Ignition:
Ignition system components, timing, spark plugs, ignition coil, distributor
Exhaust:
Exhaust system components, catalytic converter (if applicable for later models), mufflers, pipes
Maintenance:
Routine maintenance, tune-ups, fluid changes, filter replacements, belt adjustments
Troubleshooting:
Diagnostic procedures for common problems, fault finding, symptom analysis
Repair:
Step-by-step repair instructions for all major vehicle components and systems
Overhaul:
Complete overhaul procedures for engine, transmission, and other major assemblies
Disassembly Assembly:
Detailed instructions for component removal and installation
Depth:
Professional level, suitable for experienced technicians but accessible to knowledgeable DIYers. Emphasizes special aspects of Mercedes-Benz products.
Special Tools:
Identification and use of specialized Mercedes-Benz tools required for specific adjustments and repairs.
Warnings Cautions:
Highlights safety warnings, cautions, and important notes with specific symbols.
Engine Type:
Inline-6, DOHC (Double Overhead Camshaft)
Displacement:
2.8 Liters (2799 cc)
Bore X Stroke:
86.0 mm x 80.25 mm
Compression Ratio:
8.0:1 (typical)
Horsepower:
Approx. 185 PS (182 bhp / 136 kW) at 5800 rpm (DIN)
Torque:
Approx. 240 Nm (177 lb-ft) at 4250 rpm (DIN)
Fuel Delivery:
Bosch K-Jetronic Mechanical Fuel Injection
Fuel Type:
Unleaded Gasoline (Premium)
Ignition System:
Electronic Ignition with Distributor
Transmission Type:
4-speed Manual (initially), 4-speed Automatic (common option)
Transmission Type:
Optional 5-speed Manual, 4-speed Automatic (later replaced by 4-speed automatic)
Automatic Features:
Torque converter lock-up (on some later models), hydraulic control.
Length:
Approx. 4725 mm (186.0 in) for Sedan
Width:
Approx. 1785 mm (70.3 in)
Height:
Approx. 1435 mm (56.5 in) for Sedan
Wheelbase:
Approx. 2795 mm (110.0 in)
Curb Weight:
Approx. 1450 kg (3197 lbs) for Sedan
Gross Vehicle Weight Rating:
Approx. 1950 kg (4299 lbs)
Towing Capacity:
Varies by market and specific vehicle configuration, generally not emphasized.
Crash Test Performance:
Excellent for its era due to robust chassis design and safety features. No standardized ratings like modern NCAP.
Brakes:
Front ventilated discs, rear solid discs. Optional ABS (Anti-lock Braking System) on later models.
Steering:
Power-assisted recirculating ball steering.
Body Structure:
Reinforced safety cage, crumple zones, impact-absorbing steering column.
Airbags:
Not available during the primary production run. Introduced on later Mercedes models.
Seatbelts:
3-point inertia-reel seatbelts in the front, lap belts in the rear (later models may have 3-point rear belts).
Oil Change Interval:
Typically every 10,000-15,000 km (6,000-9,000 miles) or annually, depending on driving conditions and oil used.
Filter Replacement Interval:
Oil filter with every oil change. Air and fuel filters typically every 20,000-30,000 km (12,000-18,000 miles).
Tune Up Interval:
Spark plugs typically every 30,000-40,000 km (18,000-25,000 miles). Ignition timing and fuel mixture checks should be done periodically.
Engine Oil:
API SG/SH or ACEA A2/A3 rated, viscosity 10W-40 or 15W-40 recommended (check manual for precise specs).
Coolant:
Glysantin G05 or equivalent (ethylene glycol based) with corrosion inhibitors. 50/50 mix with distilled water.
Transmission Fluid:
Automatic: MB-Approval 236.1 spec (e.g., Dexron II or compatible). Manual: GL-4 rated gear oil.
Brake Fluid:
DOT 3 or DOT 4, ISO 4925 Class 3.
Common Problems:
Rusted wheel arches, battery tray, and underbody. Injector seal leaks. Timing chain stretching (M110 engine). Fuel distributor issues with K-Jetronic. Vacuum hose deterioration. Heater control valve failure.
Preventative Maintenance:
Regular undercoating and rust prevention. Consistent fluid changes. Timely replacement of worn hoses and belts. Periodic inspection of suspension and steering components.
Brand History:
Mercedes-Benz has a long-standing history of producing high-quality, durable, and technologically advanced vehicles, particularly in the luxury and engineering segments.
W123 Generation:
The W123 was the successor to the W114/W115 (Stroke-8) and was produced in sedan, coupe, estate (T-model), and long-wheelbase versions. It established Mercedes-Benz's reputation for reliability and longevity in the modern era.
280Se Variant:
The 280SE featured the larger, more powerful M110 inline-six engine, offering a balance of performance and refinement.
Production Period:
1976-1985
Manufacturing Locations:
Mainly Germany, with assembly plants in other countries.
Automotive Journalism Awards:
While not typically winning specific 'awards' in the modern sense, the W123 was widely lauded by automotive press for its build quality, comfort, and durability.
Industry Recognition:
Considered one of the most reliable and best-built Mercedes-Benz models ever produced, contributing to the brand's reputation for longevity.
Owner Satisfaction:
High owner satisfaction due to its robust nature and low cost of ownership over extended periods, despite potential for expensive repairs if neglected.
