Market Segment:
Full-size Luxury Sedan
Competitors 1984 85:
BMW 7 Series, Audi V8 Quattro, Jaguar XJ-S, Cadillac Eldorado
Vehicle Highlights:
Exceptional build quality, advanced engineering, luxurious interior, powerful V8 engine, smooth ride
Manual Value Proposition:
Empowers owners and technicians with detailed, accurate information for maintenance and repair of a complex luxury vehicle.
Engine Mechanical:
Complete overhaul, timing, valve train, lubrication, cooling, fuel injection (Bosch K-Jetronic)
Engine Electrical:
Ignition system, starter, alternator, ECU diagnostics
Transmission:
4-speed Automatic (722.3 series) - diagnostics, overhaul, fluid service
Drivetrain:
Driveshaft, differential, rear axle overhaul
Suspension:
Front and rear suspension components, shock absorbers, springs, bushings, alignment
Steering:
Power steering system, steering gearbox, tie rods, power steering fluid
Brakes:
Front and rear disc brakes, ABS (Anti-lock Braking System) components, hydraulic system, bleeding procedures
Electrical System:
Wiring diagrams, lighting, power windows, power seats, climate control, central locking, instrument cluster
Body And Chassis:
Body panels, doors, hinges, latches, interior trim, glass replacement
Climate Control:
HVAC system, R134a conversion, refrigerant service, blower motor, heater core, A/C compressor
Maintenance:
Scheduled maintenance tasks, oil changes, filter replacements, fluid checks and top-offs
Diagnostics:
Troubleshooting guides for common drivability issues, electrical faults, and mechanical problems
Repair:
Step-by-step repair instructions for all major vehicle systems
Overhaul:
Detailed procedures for engine, transmission, and differential rebuilds
Adjustments:
Carburetor (if applicable), ignition timing, valve lash adjustments
Troubleshooting Charts:
Systematic diagnostic flowcharts for common problems
Depth:
Comprehensive (from basic maintenance to full engine rebuilds and electrical diagnostics)
Diagnostic Tools:
Guidance on using specialized tools and diagnostic procedures
Engine Type:
V8, SOHC (Single Overhead Camshaft)
Displacement:
4973 cc (5.0 Liters)
Bore X Stroke:
92.0 mm x 92.4 mm
Cylinder Block Material:
Cast Iron
Cylinder Head Material:
Aluminum Alloy
Horsepower SAE Net:
180 hp @ 4200 rpm (approx.)
Torque SAE Net:
238 lb-ft @ 2500 rpm (approx.)
Fuel Injection System:
Bosch K-Jetronic CIS (Continuous Injection System)
Fuel Type:
Unleaded Premium Gasoline (91 Octane or higher recommended)
Engine Control Unit:
Bosch Electronic Control Unit (ECU) for fuel injection and ignition timing
Crash Test Data:
Era-specific safety standards, no standardized NCAP ratings available for this vintage.
ABS:
Standard Anti-lock Braking System (ABS)
Traction Control:
Optional (ASR - Acceleration Slip Regulation on some later models, less common in '84-'85)
Airbags:
Driver-side airbag became standard in late 1984/1985 models, refer to specific vehicle build.
Seatbelts:
Three-point front and rear seatbelts
Crumple Zones:
Advanced crumple zone design for its era
Audio System:
Factory AM/FM stereo with cassette player, optional premium sound system.
Controls:
Manual climate controls, mechanical dashboard gauges.
Cruise Control:
Standard cruise control system
Headlights:
Halogen headlights, manual leveling adjustment.
Connectivity Features:
Analog systems, no modern connectivity features like Bluetooth or USB.
Oil Change Interval:
Every 10,000 km (6,000 miles) or 12 months, whichever comes first (check manual for exact specification)
Transmission Fluid Service:
Every 40,000 km (25,000 miles) or 24 months (check manual for exact specification)
Engine Oil Capacity:
7.5 Liters (7.9 US Quarts) with filter
Engine Oil Viscosity:
SAE 15W-40 or 10W-40 API SG/CD rating recommended (consult manual for specific temperature ranges)
Coolant Type:
Ethylene glycol-based antifreeze (MB Specification 325.0)
Common Problems:
Wiring harness degradation (especially brittle insulation), fuel distributor leaks (K-Jetronic), vacuum line leaks, SLS (Self-Leveling Suspension) issues, climate control flap actuators, transmission cooling line leaks.
Maintenance Priority:
Regular inspection and replacement of rubber hoses, vacuum lines, and electrical connectors is crucial for reliability.
Mercedes Benz Legacy:
Pioneer in automotive safety and engineering, long history of luxury and performance vehicles.
W126 Introduction:
Introduced in 1979, the W126 replaced the W116 S-Class and set new benchmarks for luxury sedan design, aerodynamics, and safety.
W126 Facelift:
A significant facelift occurred in 1985, introducing revised bumpers, trim, and interior updates. The '84-'85 models are part of the pre-facelift W126.
Production Years:
1979-1991 (W126 generation)
Manufacturing Locations:
Sindelfingen, Germany
