Positioning:
The Mercedes-Benz W123 series, particularly the 280CE coupe, represented the pinnacle of luxury, engineering, and build quality in its segment during the late 1970s and early 1980s. It was positioned as a sophisticated, comfortable, and highly reliable grand tourer for discerning buyers.
Competitors:
Competed with other premium coupes of the era such as the BMW 6 Series (E24), Jaguar XJ-S, and occasionally larger American personal luxury coupes, though often at a higher price point and with a distinct European luxury focus.
Design Philosophy:
Emphasized robust engineering, durability, and a timeless, elegant design. The W123 chassis was renowned for its solid construction and exceptional safety features for its time.
Coupe Distinctiveness:
The 280CE offered a more stylish and sporty alternative to the sedan and wagon variants, featuring frameless door glass and a pillarless hardtop design that allowed for an expansive open-air feel when windows were lowered.
Engine:
Detailed coverage of the M110 engine (2.8L DOHC Inline-6), including fuel injection (Bosch K-Jetronic), ignition system, cooling system, lubrication system, and emission controls.
Transmission:
Coverage for both the 4-speed automatic (722.1) and 4-speed manual transmissions, including overhaul procedures, adjustments, and fluid specifications.
Drivetrain:
Detailed information on the rear-wheel drive system, including driveshaft, universal joints, differential, axles, and wheel bearings.
Suspension:
Comprehensive coverage of front independent suspension (double wishbone) and rear independent suspension (semi-trailing arm), including shock absorbers, springs, control arms, ball joints, and steering linkage.
Brakes:
Detailed procedures for the hydraulic braking system, including front and rear disc brakes, brake lines, master cylinder, brake booster (and potential vacuum issues), and parking brake.
Steering:
In-depth coverage of the recirculating ball steering system, including steering box, power steering pump, hydraulic lines, and steering column.
Electrical System:
Extensive wiring diagrams, troubleshooting guides for lighting, gauges, wipers, horn, power windows, power locks, climate control, and accessory circuits.
Climate Control:
Coverage of the HVAC system, including blower motor, heater core, evaporator, refrigerant system (R12), and control mechanisms.
Body:
Information on body panel removal/installation, door mechanisms, window regulators, convertible top mechanisms (if applicable to specific trims, though the 280CE is primarily coupe), seals, and trim.
Body Interior:
Procedures for dashboard removal, seat installation/removal, headliner, and interior trim components.
Maintenance:
Routine maintenance tasks such as oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt adjustments, and lubrication points.
Troubleshooting:
Systematic diagnostic procedures for common problems, including engine performance issues, starting problems, electrical faults, and braking concerns.
Repair:
Step-by-step repair instructions for major components, including engine overhaul, transmission rebuild, suspension and steering system repairs, brake system overhauls, and electrical component replacement.
Engine Overhaul:
Detailed engine disassembly, cleaning, inspection, and reassembly procedures, including piston ring replacement, bearing checks, cylinder head work, and valve adjustments.
Fuel System Service:
Instructions for fuel pump testing, fuel filter replacement, fuel injector cleaning, and calibration of the K-Jetronic fuel distributor.
Cooling System Service:
Procedures for radiator replacement, water pump replacement, thermostat testing, coolant flushing, and leak detection.
Brake System Service:
Instructions for brake pad and rotor replacement, brake caliper overhaul, brake line bleeding, and master cylinder replacement.
Electrical Diagnostics:
Guidance on using multimeters and oscilloscopes for diagnosing electrical faults, checking sensor outputs, and tracing wiring issues.
Bodywork Repair:
Information on rust repair, panel alignment, welding procedures (though detailed body shop techniques may be limited), and sealing.
Depth:
Comprehensive, covering everything from basic owner maintenance to in-depth engine and transmission rebuilds. Suitable for professional mechanics and experienced DIY enthusiasts.
Crash Test Data:
While formal government crash test ratings (like NHTSA) were less standardized in this era, the W123 chassis was engineered with significant safety features for its time, including a robust safety cell, crumple zones, and a strong chassis construction.
Brakes:
Four-wheel disc brakes, with the front typically ventilated.
Steering:
Power steering for improved maneuverability.
Airbags:
Not standard; early models did not feature airbags. Later versions or optional upgrades might exist but were not common.
Seatbelts:
Three-point inertia-reel seatbelts for front occupants, lap belts for rear occupants.
Body Construction:
Reinforced passenger compartment, energy-absorbing steering column.
Oil Change:
Every 7,500 - 10,000 miles (12,000 - 15,000 km) or annually, whichever comes first. Recommended use of high-quality synthetic oil.
Transmission Fluid Service:
Automatic: Every 30,000 - 50,000 miles (50,000 - 80,000 km). Manual: Inspect annually, change fluid if indicated by noise or shifting issues.
Spark Plugs:
Inspect every 15,000 miles (24,000 km), replace as needed (typically every 30,000 miles / 50,000 km).
Coolant Flush:
Every 2-3 years or 30,000 miles (50,000 km).
Engine Oil:
SAE 10W-40 or 20W-50 (depending on climate) API SG or higher. Synthetic oils are highly recommended for longevity.
Coolant:
Mercedes-Benz approved anti-freeze/anti-corrosion coolant (e.g., G05 based) mixed 50/50 with distilled water.
Brake Fluid:
DOT 3 or DOT 4.
Power Steering Fluid:
ATF Dexron II or III.
Engine Oil Leaks:
Common leaks from valve cover gaskets, oil pan gaskets, and front/rear main seals due to aging rubber and cork seals.
K-Jetronic:
Can develop issues with the air flow meter, control pressure regulator (CPR), or fuel distributor leading to rough running, poor starting, or fuel leaks. Sensitivity to air leaks in vacuum hoses.
Cooling System:
Radiator leaks, thermostat sticking, and degradation of hoses and plastic coolant reservoir (if equipped) are common with age.
Suspension Wear:
Worn ball joints, tie rod ends, and bushings can lead to steering looseness and premature tire wear.
Electrical Faults:
Corroded connections, failing relays (especially fuel pump relay), and brittle wiring insulation can cause intermittent electrical issues.
Rust:
Prone to rust in common areas like wheel wells, rocker panels, around the windshield, and door bottoms, especially in regions with road salt.
Window Regulators:
Manual and power window regulators can fail over time, leading to windows not operating or falling into the door.
Heritage:
Mercedes-Benz has a long-standing reputation for engineering excellence, luxury, and durability dating back to the early 20th century. The W123 generation built upon this legacy, aiming for unparalleled reliability and comfort.
W123 Lineage:
The W123, launched in 1975, replaced the W114/W115 models. The coupe variant (C123) was introduced shortly after, offering a sleeker profile. The 280CE was a top-tier model within the W123 coupe range.
Production Period:
W123 Coupe (C123): 1977-1985.
Manufacturing Locations:
Primarily manufactured in Germany.
Sales Figures:
The W123 series as a whole was a global sales success for Mercedes-Benz, renowned for its durability and was produced in significant numbers. Specific coupe sales figures are lower than sedan/wagon variants.
