Vehicle Segment:
Luxury Grand Tourer / Sports Car
Brand Perception:
High-performance, sophisticated engineering, build quality, and luxury
Competitors:
Porsche 911, BMW 8 Series (E31), Jaguar XJS, Chevrolet Corvette (C4)
Highlight:
Electrically operated soft top and hardtop (optional), advanced suspension, powerful inline-six engine, robust build quality
Manual Value:
Provides essential, in-depth information for owners and technicians to maintain and repair this complex luxury vehicle.
Primary Coverage:
Service and Repair
Secondary Coverage:
Maintenance, Diagnostics, Troubleshooting, Technical Data
Estimated Pages:
Approx. 1000-1500+ (typical for comprehensive Mercedes-Benz factory manuals of this era)
Type:
Official Factory Service Manual (Electronic/Software)
Format:
Software/Digital (likely searchable PDF or proprietary viewer)
Powertrain:
Engine (M104), Transmission (722.5 5-Speed Automatic)
Chassis:
Suspension (Hydropneumatic front, Independent rear), Steering (Power-assisted recirculating ball), Brakes (Front Ventilated Discs, Rear Solid Discs, ABS)
Electrical:
Engine Control Unit (ECU), Fuel Injection System (Bosch KE-Jetronic), Ignition System, Lighting, Instrumentation, Power Accessories, Convertible Top System, Anti-theft System
Body:
Body Structure, Exterior Panels, Convertible Top Mechanism, Interior Trim, Seating
Routine Maintenance:
Oil change, filter replacement, fluid checks and top-offs, spark plug replacement, belt inspection and replacement
Diagnostics:
Fault code retrieval (OBD-I), component testing, electrical circuit tracing, fuel system diagnostics, engine performance troubleshooting
Repair Overhaul:
Engine rebuild procedures, transmission overhaul, suspension component replacement, brake system repair, convertible top mechanism repair, electrical component replacement
Adjustment Calibration:
Idle speed adjustment, ignition timing (if applicable), convertible top alignment, headlight aiming
Depth:
Comprehensive: Covers everything from basic fluid changes and inspections to complete engine and transmission rebuilds, including detailed electrical schematics and diagnostic procedures.
Detail Level:
Expert-level detail with torque specifications, clearances, diagnostic flowcharts, and component removal/installation instructions.
Engine Type:
Inline 6-cylinder, Double Overhead Camshaft (DOHC), 24 valves
Displacement:
3.0 Liters (2960 cc)
Bore X Stroke:
89.9 mm x 78.4 mm
Compression Ratio:
10.0:1
Horsepower:
228 hp @ 6400 rpm
Torque:
200 lb-ft (271 Nm) @ 4400 rpm
Fuel Delivery:
Bosch KE-Jetronic Electronic Fuel Injection with Lambda Control
Fuel Type:
Premium Unleaded Gasoline (91+ Octane)
Type:
Electronic Ignition System with Knock Control
Type:
Water-cooled, Thermostatically Controlled
Oil Capacity:
7.5 Liters (7.9 US Quarts) with filter change
Recommended Oil Viscosity:
SAE 15W-40 or 10W-30 (depending on climate, check manual for specifics)
Type:
4-speed Automatic with Lock-up Torque Converter (722.4, later 722.5 5-speed available on some models, confirm for specific 1992 300SL variant)
Shift Modes:
Standard, Economy (E) and Sport (S) modes (722.5)
Fluid Specification:
MB 236.1 or MB 236.3 Automatic Transmission Fluid (ATF)
Capacity:
Approx. 7.5 Liters (dry fill, check manual for specific refill amounts)
NHTSA Rating:
Not directly applicable in modern format; designed to high safety standards for its era.
ABS:
Standard Anti-lock Braking System (ABS)
Traction Control:
Optional (ASR - Acceleration Slip Regulation on some models)
Airbags:
Driver's Airbag Standard, Passenger Airbag Optional/Standard on later production.
Rollover Protection:
Automatic roll bar deployment system
Seatbelts:
Three-point inertia-reel seatbelts with pretensioners
Audio System:
Premium sound system (e.g., Becker or Bose), often with cassette player and optional CD changer.
Climate Control:
Automatic climate control with air conditioning
Cruise Control:
Standard electronic cruise control
Memory Seats:
Optional electrically adjustable seats with memory function
Bluetooth:
Not available in original configuration. Aftermarket solutions exist.
Oil Service:
Every 7,500 miles (12,000 km) or 12 months, whichever comes first.
Major Service:
Detailed intervals for spark plugs, transmission fluid, coolant, brake fluid, and other components outlined in the factory service manual.
Engine Oil:
Refer to manual for specific API rating and viscosity based on climate (e.g., MB 229.1 compliant oils are often suitable).
Coolant:
Mercedes-Benz Approved Antifreeze/Coolant (e.g., G05 or similar, consult manual for specific part number/specification)
Brake Fluid:
DOT 3 or DOT 4
Wiring Harness:
Biodegradable insulation on engine wiring harnesses can degrade over time, leading to electrical issues.
Convertible Top Hydraulics:
Hydraulic cylinders and lines for the convertible top can leak or fail.
Mass Air Flow Sensor:
Can become dirty or fail, affecting engine performance.
Suspension Bushings:
Rubber bushings in the suspension can wear out, leading to noise and handling degradation.
Heritage:
Mercedes-Benz has a long history of producing high-quality, innovative, and luxurious automobiles, particularly known for their pioneering safety features and engineering excellence in sports cars and grand tourers.
Predecessor:
Mercedes-Benz R107 SL-Class
Generation Start:
R129 generation introduced for the 1990 model year.
Design Philosophy:
The R129 was a complete redesign, offering significantly improved safety, comfort, and technology compared to its predecessor, with a focus on a refined yet sporty driving experience.
Production Years:
1989-2001
Manufacturing Location:
Germany (Sindelfingen plant)
