Positioning:
The Mercedes-Benz W124 chassis, particularly the E320 Wagon, represented the pinnacle of luxury, engineering, and build quality in its era. This manual caters to owners and mechanics who value the longevity and performance of these iconic vehicles.
Competitors Era:
BMW 5 Series Touring, Audi 100/A6 Avant, Volvo 940/960 Estate, Saab 9000 Wagon.
Vehicle Strengths:
Exceptional build quality, robust powertrain, comfortable ride, durable interior materials, excellent safety for its time.
Value:
Provides essential information for maintaining and repairing the W124 E320 Wagon, empowering owners to perform tasks themselves or better understand professional service, thereby extending the vehicle's lifespan and preserving its value.
Engine Mechanical:
Complete overhaul, component testing, timing, valve adjustment, piston/ring inspection, crankshaft/bearing checks.
Engine Management:
Fuel injection (Bosch KE-Jetronic/HFM), ignition system, electronic control unit (ECU) diagnostics, sensor testing, emissions control systems.
Transmission Automatic:
722.3, 722.4, 722.5 (4-speed and 5-speed variants), overhaul, adjustment, hydraulic control, torque converter.
Drivetrain:
Rear-wheel drive, differential, driveshaft, CV joints, axle shafts.
Suspension:
Front independent (struts, control arms, ball joints), rear independent (multi-link), springs, shock absorbers, sway bars, bushings.
Steering:
Power steering system, steering gearbox, tie rods, steering column, alignment specifications.
Brakes:
Front and rear disc brakes, ABS (Anti-lock Braking System) components and diagnostics, brake fluid specifications, master cylinder, calipers, lines.
Electrical System:
12-volt system, battery, charging system (alternator), starter motor, wiring diagrams, fuses, relays, lighting, horn.
Body And Chassis:
Body construction, panel replacement, door mechanisms, glass, seals, rust prevention, chassis lubrication.
HVAC:
Heating, ventilation, and air conditioning system, refrigerant types, compressor, evaporator, condenser, blower motor, climate control module.
Interior:
Seat adjustments, trim panel removal, dashboard components, seat belts, interior lighting.
Preventative Maintenance:
Oil changes, filter replacements, fluid checks and top-offs, belt inspections, spark plug replacement, brake pad replacement.
Troubleshooting:
Systematic diagnostic procedures for common and uncommon issues, fault code interpretation (where applicable), wiring harness testing.
Repair And Overhaul:
Detailed step-by-step instructions for component removal, repair, and reinstallation for all major systems.
Component Replacement:
Alternator, starter, water pump, fuel pump, master cylinder, brake rotors, shock absorbers, ball joints, etc.
Adjustment Procedures:
Idle speed, throttle linkage, parking brake, clutch (manual models, though less common for this engine), transmission detent.
Electrical Diagnostics:
Use of multimeters, oscilloscopes, troubleshooting wiring diagrams, component testing.
Specifications And Tolerances:
Torque values for all fasteners, clearance measurements, pressures, electrical resistance values.
Depth:
Comprehensive, covering everything from routine maintenance to complete engine and transmission rebuilds.
Detail Level:
Factory-level detail with exploded views, detailed diagrams, and precise specifications.
Target Audience:
Professional technicians and experienced DIY enthusiasts.
Engine Code:
M104.992 (for 3.2L US spec)
Engine Type:
Inline 6-cylinder, DOHC, 4 valves per cylinder
Displacement:
3.2 Liters (3199 cc)
Horsepower:
Approx. 217 hp @ 5500 rpm (US spec)
Torque:
Approx. 228 lb-ft @ 4000 rpm (US spec)
Fuel Delivery:
Electronic Fuel Injection (EFI) - Bosch KE-Jetronic (early) or HFM (later models within the 93-95 range).
Fuel Type:
Premium Unleaded Gasoline (91 octane or higher recommended)
Ignition Type:
Distributorless Ignition System (DIS) with coil packs.
Cooling Method:
Liquid-cooled, pressurized system with thermostat and fan.
Oil Capacity:
Approx. 8.5 quarts (8.0 Liters) with filter change.
Oil Specification:
API SG or higher, SAE 15W-40 or 10W-30 (depending on climate/seasonal use, consult manual for exact specs).
Oil Change:
Every 7,500 miles (12,000 km) or annually, whichever comes first (check manual for specific conditions).
Transmission Service:
Every 30,000 miles (48,000 km) for fluid and filter change is generally recommended for longevity. Consult manual for specific intervals.
Spark Plugs:
Approx. 60,000 miles (96,000 km) depending on plug type (e.g., platinum).
Coolant Flush:
Every 2 years or 30,000 miles (48,000 km).
Coolant:
MB Approved Antifreeze/Coolant (e.g., G05 or similar silicate-free coolant).
Wiring Harness:
Degradation of insulation on engine wiring harnesses (known as 'the black death' by some enthusiasts) due to age and material composition, leading to various electrical faults.
Head Gasket:
While generally robust, head gasket leaks can occur with age and mileage, particularly if the engine has been overheated.
Window Regulators:
Plastic components in power window regulators can become brittle and break.
Sunroof Drain Tubes:
Clogged sunroof drain tubes can lead to water ingress into the cabin, causing rust and electrical issues.
Mass Air Flow Sensor:
MAF sensor can become dirty or fail, affecting engine performance and fuel economy.
Automatic Transmission Converters:
Torque converter lock-up issues or failure can occur with high mileage.
Heritage:
Mercedes-Benz has a long-standing reputation for engineering excellence, safety, and luxury, dating back to the early 20th century. The W124 generation continued this legacy.
W124 Generation:
The W124 chassis was introduced in 1984 as a successor to the W123. It was renowned for its robust engineering, aerodynamic design, and a wide range of body styles, including sedan, coupe, convertible, and the versatile wagon (S124).
E Class Rebranding:
In 1993, Mercedes-Benz rebranded its model lines. The W124 series became the E-Class, with the E320 designation indicating the 3.2-liter engine.
Production Years:
The W124 chassis was produced from 1984 to 1997. The E320 Wagon was specifically produced from 1992 through 1995 for the US market.
Manufacturing Location:
Germany (primary), South Africa, others.