Engine Mechanical:
Engine assembly, cylinder head, crankshaft, pistons, connecting rods, valve train, timing chain, lubrication system, cooling system, fuel injection system (Bosch K-Jetronic), exhaust system.
Engine Electrical:
Ignition system, starter system, charging system (alternator), fuel pump, fuel injectors, engine control unit (ECU) diagnostics, wiring diagrams.
Transmission:
Automatic transmission (e.g., 4-speed 722.1), manual transmission (if applicable), clutch system (manual), gear selection, torque converter, transmission fluid system, valve body.
Drivetrain:
Rear axle, differential, drive shafts, universal joints, wheel bearings.
Suspension:
Front suspension (e.g., double wishbone), rear suspension (e.g., multi-link), shock absorbers, springs, control arms, bushings, steering knuckles.
Steering:
Power steering system, steering column, steering gearbox, tie rods, steering linkage.
Brakes:
Front and rear disc brakes, hydraulic system, brake calipers, brake pads, brake rotors, brake master cylinder, brake booster, parking brake system.
Electrical System:
Battery, starter, alternator, lighting system (headlights, taillights, interior lights), fuses, relays, wiring harnesses, dashboard instruments, horn, wipers, washers.
HVAC:
Heating, ventilation, and air conditioning (HVAC) system, blower motor, heater core, A/C compressor, refrigerant system, climate controls.
Bodywork:
Body panels, doors, hood, trunk, bumpers, glass, seals, interior trim, rust prevention, body repair techniques.
Maintenance:
Oil changes, filter replacements (oil, fuel, air), spark plug replacement, coolant flushes, brake fluid changes, transmission fluid changes, differential fluid changes, lubrication points.
Troubleshooting:
Diagnostic procedures for common engine, transmission, electrical, and HVAC issues. Fault code interpretation (if applicable).
Repair:
Step-by-step repair instructions for all major mechanical and electrical components, including engine rebuilds, transmission overhauls, brake system repairs, suspension component replacement.
Installation:
Instructions for replacing or installing components like alternators, starters, fuel pumps, brake calipers, shock absorbers.
Adjustments:
Carburetor adjustment (if applicable to variants), valve adjustments, ignition timing adjustments, idle speed adjustments.
Depth:
Expert level, covering everything from basic preventive maintenance to full engine and transmission overhauls, including detailed diagnostic procedures and electrical system troubleshooting.
Engine Type:
Inline-six, naturally aspirated gasoline engine.
Displacement:
2.8 Liters (2799 cc).
Bore X Stroke:
86.5 mm x 80.25 mm (typical for M110).
Compression Ratio:
Typically 8.0:1 or 9.0:1 depending on market and specific variant.
Horsepower:
Approximately 145-160 PS (143-158 hp) depending on specific engine variant and market regulations (e.g., DIN vs. SAE).
Torque:
Approximately 230-235 Nm (170-173 lb-ft) depending on specific engine variant.
Fuel Delivery:
Bosch K-Jetronic mechanical fuel injection.
Fuel Type:
Unleaded gasoline (Premium Octane recommended).
Fuel Pump Type:
Mechanical, often a multi-cylinder diaphragm pump.
Crash Test Performance:
While specific official ratings from modern agencies are rare for this era, the W123 was known for its robust safety cage, crumple zones, and strong chassis structure, earning a reputation for durability and occupant protection.
Braking System:
Four-wheel disc brakes, often with front vented discs. Anti-lock braking system (ABS) was an optional feature on later models or specific variants.
Airbags:
Driver's airbag became available as an option on later W123 models, but was not standard on most 280E variants.
Seat Belts:
Standard 3-point seat belts in the front and rear.
Structure:
Reinforced passenger cell, crumple zones front and rear, impact-absorbing steering column.
Oil Change Interval:
Typically every 7,500-15,000 km (4,600-9,300 miles) or annually, whichever comes first, depending on usage and oil quality. Check manual for specific recommendation.
Filter Replacement Interval:
Oil filter with every oil change. Air filter and fuel filter typically every 30,000-60,000 km (18,000-37,000 miles).
Spark Plug Replacement:
Typically every 40,000-60,000 km (25,000-37,000 miles).
Coolant Flush:
Every 2-3 years or 40,000-60,000 km (25,000-37,000 miles).
Engine Oil Specification:
API SG or higher, SAE 10W-40 or 15W-40 recommended for general use. Refer to manual for seasonal variations.
Engine Oil Capacity:
Approx. 7.0 liters (7.4 US quarts) with filter change.
Coolant Specification:
Ethylene glycol-based antifreeze, mixed with distilled water (50/50 ratio). Mercedes-Benz specification 325.0 is often cited for this era.
Transmission Fluid Specification:
For automatic: MB spec 236.1 (e.g., Dexron II or equivalent). For manual: GL-4 gear oil.
Brake Fluid Specification:
DOT 3 or DOT 4 (check manual for definitive recommendation).
Rust:
Common issue, particularly on wheel arches, sills, door bottoms, and around window seals. Meticulous inspection and prevention are key.
Fuel System K Jetronic:
Can become clogged or develop leaks. Control pressure regulator and air flow meter are common service items.
Vacuum Lines:
Degradation of rubber vacuum lines can lead to various drivability issues and air leaks.
Thermo Time Switch:
Failure can affect cold starting and idle stability.
Suspension Bushings:
Wear on control arm bushings and ball joints is common and affects ride and handling.
Mercedes Benz Legacy:
Mercedes-Benz, established in 1926, is renowned for pioneering automotive engineering, safety, and luxury.
W123 Lineage:
The W123 replaced the W114/W115 series and was produced from 1975 to 1986. It was a major success, solidifying Mercedes-Benz's reputation for quality and reliability.
280E Positioning:
The 280E was positioned as a high-performance, luxury model within the W123 range, offering smooth inline-six power and refinement.
Production Years:
W123 series: 1975-1986. The 280E variant was produced throughout this period, with minor updates.
Manufacturing Locations:
Primary manufacturing in Stuttgart, Germany, with assembly plants in other countries as well.
