🏷️ Basic Information

Make:

Mercedes-Benz

Model:

240D

Model Code:

W123 (Sedan/Saloon)

Engine Code:

OM616 (2.4L Diesel)

👋 Introduction

Positioning:

The Mercedes-Benz 240D (W123) was a cornerstone of Mercedes-Benz's reputation for durability, luxury, and engineering excellence in the late 1970s and early 1980s. It appealed to buyers seeking reliable, fuel-efficient, and comfortable transportation with the prestige of the Mercedes-Benz brand.

Competitors:

Competed with other executive sedans of the era, though its diesel engine offered a distinct advantage in fuel economy and longevity, differentiating it from gasoline-powered rivals from brands like BMW, Audi, and Volvo.

Features:

Robust build quality, distinctive W123 styling, reliable OM616 diesel engine, comfortable ride, focus on safety and longevity.

📋 Manual Details

Years Covered:

1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985

Estimated Pages:

N/A (Digital Format)

Type:

Factory Service Workshop Manual

Language:

English

Format:

Digital Download (likely PDF)

📖 Manual Coverage

Engine Mechanical:

Detailed overhaul procedures, component testing, specifications, troubleshooting for the OM616 diesel engine.

Fuel System:

Injection pump (Bosch VE), injectors, fuel lines, filters, troubleshooting of diesel fuel delivery.

Cooling System:

Radiator, water pump, thermostat, hoses, coolant specifications, flush and fill procedures.

Lubrication System:

Oil pump, oil filter, oil cooler (if equipped), oil specifications, change intervals.

Exhaust System:

Exhaust manifold, pipes, muffler, catalytic converter (later models), emission control systems.

Transmission Manual:

4-speed and 5-speed manual transmissions, clutch operation, overhaul, fluid specifications.

Transmission Automatic:

Automatic transmission (e.g., 722.1), torque converter, hydraulic system, overhaul, fluid specifications.

Drivetrain Rear Axle:

Differential, drive shafts, axle shafts, wheel bearings, lubrication, overhaul.

Suspension Front:

Independent front suspension, control arms, ball joints, springs, shock absorbers, steering knuckle, alignment specifications.

Suspension Rear:

Independent rear suspension (IRS) or solid axle depending on body style variant, trailing arms, springs, shock absorbers, alignment specifications.

Steering System:

Power steering system, steering box, tie rods, steering column, fluid specifications, troubleshooting.

Brakes Front:

Disc brakes, calipers, pads, rotors, brake fluid specifications, bleeding procedures.

Brakes Rear:

Disc brakes or drum brakes (depending on variant), parking brake system, fluid specifications, bleeding procedures.

Electrical System 12V:

Battery, alternator, starter motor, wiring diagrams, fuses, relays, lighting systems.

Instrumentation Gauges:

Speedometer, tachometer, fuel gauge, temperature gauge, warning lights, cluster repair.

Lighting System:

Headlights, taillights, turn signals, interior lighting, bulb specifications.

HVAC System:

Heating, ventilation, and air conditioning (if equipped), blower motor, heater core, refrigerant handling (later models).

Body Panels:

Door panels, hood, trunk lid, fenders, bumpers, trim, alignment, repair.

Glass Windows:

Windshield, side windows, rear window, seals, regulator mechanisms.

Interior Trim:

Seats, dashboard, door panels, headliner, carpet, removal and installation.

Chassis Frame:

Frame inspection, rust repair, structural components.

Routine Maintenance:

Oil changes, filter replacements, fluid checks and top-offs, lubrication points, spark plug replacement (gasoline variants, not 240D), timing belt inspection/replacement (N/A for OM616).

Engine Overhaul:

Complete engine disassembly, inspection, measurement, rebuilding of internal components (pistons, rings, bearings, valves, etc.).

Transmission Repair:

Manual and automatic transmission disassembly, component replacement, reassembly, adjustments.

Brake Service:

Pad/shoe replacement, rotor/drum machining or replacement, caliper/wheel cylinder rebuilding, brake line replacement, bleeding.

Suspension Component Replacement:

Ball joint, tie rod end, control arm, shock absorber, spring replacement.

Electrical Troubleshooting:

Diagnosis of electrical faults using wiring diagrams, testing of components.

Diagnostics:

Troubleshooting guides for various systems, identifying common problems and their solutions.

Body Repair:

Dent removal, panel replacement, rust treatment, welding procedures.

HVAC Service:

Component replacement, leak detection, refrigerant handling (where applicable).

Depth:

Comprehensive, covering full vehicle teardown, repair, and reassembly. Suitable for professional technicians and experienced DIYers.

📊 Manual Specifications

Quality:

High-resolution scans of original factory documentation, typically searchable text within PDFs.

Print Readability:

Designed for clarity and ease of reading in digital format. Print quality is dependent on user's printer.

Binding:

N/A (Digital Download)

Paper:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Type:

Inline-4 Cylinder Diesel

Engine Code:

OM616.912

Displacement:

2399 cc (2.4 Liters)

Bore X Stroke:

87.0 mm x 92.4 mm

Compression Ratio:

21.0:1

Horsepower Gross SAE:

72 hp @ 4000 rpm (approx.)

Torque Gross SAE:

107 lb-ft @ 2400 rpm (approx.)

Injection Type:

Bosch Inline Mechanical Fuel Injection (VE Pump)

Fuel Type:

Diesel Fuel

🔧 Transmission

Type:

4-speed Manual

Type:

4-speed Automatic (722.1)

Clutch:

Single dry plate, hydraulic actuation (manual transmission).

Manual Fluid:

API GL-4 Gear Oil, SAE 75W-90 or 80W-90

Automatic Fluid:

Dexron II Automatic Transmission Fluid

📐 Dimensions

Wheelbase:

2794 mm (110 inches)

Length:

4735 mm (186.4 inches)

Width:

1788 mm (70.4 inches)

Height:

1438 mm (56.6 inches)

Curb Weight Approx:

1460 kg (3219 lbs)

Gross Vehicle Weight Rating Approx:

1900 kg (4189 lbs)

🛡️ Safety Features

Historical Safety Standards:

Designed to meet safety standards of the era, featuring crumple zones, safety steering column, and robust body structure.

Braking System:

Dual-circuit hydraulic braking system with front discs and rear discs or drums. Power assist standard.

Steering Type:

Recirculating ball type, with optional power assist.

Body Construction:

Reinforced passenger cell, energy-absorbing front and rear sections.

Seatbelts:

Standard 3-point front seatbelts, lap belts for rear passengers.

💡 Technology Features

Audio System:

Original systems typically featured AM/FM radio and cassette players. Aftermarket upgrades are common.

ABS Availability:

Anti-lock Braking System (ABS) was optional on some later models, but not standard across the range.

Connectivity Features:

No advanced connectivity features by modern standards. Focus was on mechanical reliability and driver control.

🔧 Maintenance

Oil Change Interval:

Every 5,000 miles or 6 months, whichever comes first.

Air Filter Replacement:

Every 15,000 miles or annually.

Fuel Filter Replacement:

Every 10,000 miles or annually, depending on fuel quality.

Engine Oil Spec:

API CD or CE rated Diesel Engine Oil, SAE 15W-40 or 10W-30 (depending on climate).

Coolant Spec:

Mercedes-Benz Specification 325.0 (Antifreeze/Coolant Concentrate), mixed 50/50 with distilled water.

Brake Fluid Spec:

DOT 3 or DOT 4 Hydraulic Brake Fluid.

Common Wear Items:

Glow plugs, fuel injection pump seals, vacuum lines, front suspension bushings and ball joints, exhaust system components, radiator and hoses.

Diesel Specific Concerns:

Cold start performance, potential for air in fuel system if not bled properly after filter changes, valve adjustment (though less frequent than gasoline).

📚 Vehicle History

Heritage:

Mercedes-Benz has a long-standing reputation for engineering, luxury, and durability, dating back to the invention of the automobile. The 240D embodies these core values.

W123 Platform:

The W123 chassis, introduced in 1976, replaced the W114/W115 series. It was known for its exceptional build quality and refined engineering, setting new benchmarks for its class.

Production Years:

1976-1985 (W123 Diesel Sedan)

Manufacturing Locations:

Primarily Germany, with production also occurring in other global facilities.

🏆 Awards & Recognition

Market Reputation:

Widely regarded as one of the most robust and reliable Mercedes-Benz models ever produced, often cited for its longevity and ability to accumulate high mileage.