The 1986 Mercedes 420 SEL is a luxury executive sedan featuring a 4.2L V8 engine, advanced safety systems, premium interior amenities, and sophisticated engineering. This comprehensive manual covers vehicle operation, maintenance schedules, technical specifications, and troubleshooting procedures to ensure optimal performance and longevity of your Mercedes-Benz.
Key components: 4.2L V8 engine, automatic transmission, power steering, ABS braking system, climate control, power windows, central locking system.
| Feature | Description |
|---|---|
| Engine | 4.2L V8 M116 gasoline engine |
| Transmission | 4-speed automatic with torque converter |
| Braking System | 4-wheel disc brakes with ABS |
| Suspension | Independent front and rear with self-leveling |
| Fuel System | Electronic fuel injection |
| Seating Capacity | 5 passengers with leather upholstery |
| Curb Weight | Approximately 3,750 lbs |
| Fuel Capacity | 23.8 gallons |
| Wheelbase | 121.1 inches |
| Overall Length | 208.7 inches |
The instrument cluster provides comprehensive vehicle information and warning indicators.
WARNING! Address warning lights immediately to prevent vehicle damage.
Access vehicle functions through dashboard and steering column controls.
CAUTION! Familiarize yourself with all controls before driving.
Regular maintenance ensures optimal performance and reliability.
Every 3,000 miles: Oil and filter change, tire rotation
Every 7,500 miles: Air filter replacement, brake inspection
Every 15,000 miles: Spark plugs, fuel filter, transmission fluid
Every 30,000 miles: Coolant flush, brake fluid replacement
Every 60,000 miles: Timing chain inspection, major service
Proper driving techniques for optimal vehicle performance.
Tip: Avoid rapid acceleration and hard braking for better fuel economy.
Advanced safety features for occupant protection.
WARNING! Regular safety system inspection is mandatory.
Comprehensive electrical components and operation.
| Component | Specification |
|---|---|
| Battery | 12V, 70Ah maintenance-free |
| Alternator | 80-amp output |
| Starter | 1.4kW reduction gear |
| Fuses | Located in dashboard and engine compartment |
| Lighting | Halogen headlights with automatic leveling |
Proper care preserves vehicle appearance and value.
Exterior: Wash weekly with pH-balanced car shampoo; wax quarterly
Interior: Vacuum carpets; clean leather with appropriate conditioner
Engine: Keep compartment clean; check fluid levels weekly
CAUTION! Use only Mercedes-Benz approved cleaning products.
Original warranty coverage and service requirements.
Basic Warranty: 4 years/50,000 miles
Powertrain: 4 years/50,000 miles
Rust Perforation: 4 years/unlimited mileage
Emissions: 2 years/24,000 miles (federal requirements)
For service: Contact authorized Mercedes-Benz dealership
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | Battery, fuel, ignition | Check battery charge; verify fuel delivery; inspect spark plugs |
| Rough idle | Spark plugs, air filter | Replace spark plugs; clean or replace air filter |
| Brake vibration | Warped rotors | Resurface or replace brake rotors |
| Electrical issues | Alternator, battery | Test charging system; load test battery |
| Overheating | Coolant, thermostat | Check coolant level; replace thermostat if stuck |
Service: Authorized Mercedes-Benz service centers only
Emergency: Mercedes-Benz Roadside Assistance 1-800-FOR-MERCEDES