The 1987 Mercedes 420SEL is a luxury sedan featuring a 4.2L V8 engine, rear-wheel drive, 4-speed automatic transmission, advanced suspension system, comprehensive electrical systems, and premium interior amenities. This service manual covers maintenance procedures, technical specifications, troubleshooting, and repair guidelines for proper vehicle upkeep. Below are key sections for specifications, maintenance schedules, systems overview, troubleshooting, and service procedures.
Technical specifications for the 1987 Mercedes 420SEL luxury sedan.
| Specification | Details |
|---|---|
| Engine Type | 4.2L V8 M116/M117 gasoline engine |
| Displacement | 4196 cc |
| Power Output | 201 hp @ 5200 rpm |
| Torque | 228 lb-ft @ 3500 rpm |
| Transmission | 4-speed automatic (722.3) |
| Drivetrain | Rear-wheel drive |
| Fuel System | Bosch K-Jetronic fuel injection |
| Brakes | Four-wheel disc brakes with ABS |
| Suspension | Independent front and rear with hydropneumatic self-leveling |
| Wheelbase | 121.1 inches |
Recommended maintenance intervals for optimal vehicle performance.
WARNING! Use only Mercedes-Benz approved fluids and parts. Follow torque specifications precisely.
Comprehensive guide to the 4.2L V8 engine maintenance and repair.
CAUTION! Engine components are precision parts; handle with care and use proper tools.
The 420SEL features advanced hydropneumatic self-leveling suspension and power steering system.
Front Suspension: Double wishbone with hydropneumatic struts, stabilizer bar
Rear Suspension: Multi-link with hydropneumatic struts, self-leveling system
Steering: Recirculating ball power steering, 16.1:1 ratio
Hydraulic System: Fluid level check, pump replacement, strut service procedures. Alignment Specifications: Camber, caster, and toe settings with adjustment procedures.
Four-wheel disc brakes with Bosch anti-lock braking system (ABS).
Tip: Always use Mercedes-Benz approved brake fluid DOT 4.
Comprehensive electrical system including charging, starting, and accessory systems.
WARNING! Disconnect battery before electrical work to prevent short circuits.
Bosch K-Jetronic mechanical fuel injection system maintenance.
Fuel Pump: Electric in-tank and main pump testing. Fuel Filter: Replacement every 15,000 miles. Injectors: Testing and cleaning procedures. Cold Start Valve: Operation and testing. Fuel Pressure Regulator: Adjustment and replacement. Air Flow Sensor: Plate movement and control pressure.
Pressurized cooling system with electric fan and thermostat control.
Radiator: Aluminum core with plastic tanks
Water Pump: Centrifugal type with replacement procedure
Thermostat: 87°C opening temperature
Coolant: Mercedes-Benz antifreeze/water mixture 50/50
CAUTION! Never open radiator cap when engine is hot - risk of severe burns.
Luxury interior features and body maintenance procedures.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine cranks but won't start | Fuel delivery, ignition | Check fuel pressure, spark plugs, ignition coil |
| Rough idle | Vacuum leaks, dirty injectors | Inspect vacuum hoses, clean K-Jetronic components |
| Transmission shifts hard | Fluid level, throttle linkage | Check ATF level, adjust throttle cable |
| ABS light on | Wheel sensor, hydraulic unit | Test wheel sensors, check ABS relay |
| Electrical issues | Battery, alternator, grounds | Test charging system, clean battery connections |
Technical Support: Contact authorized Mercedes-Benz service center
Parts: Genuine Mercedes-Benz parts recommended for all repairs