🏷️ Basic Information

Make:

Mercedes-Benz

Model:

SL-Class

Model Code:

R129

Year:

1994

Chassis Code:

R129

Engine Codes:

M104.980 (3.2L), M119.970 (5.0L), M119.974 (6.0L AMG)

👋 Introduction

Positioning:

The Mercedes-Benz SL-Class (R129) was positioned as a premier luxury grand tourer, a sophisticated two-seater convertible that blended performance, comfort, and cutting-edge automotive technology of its era.

Competitors:

Competed with other high-end luxury convertibles such as the Porsche 911 Cabriolet, BMW 8 Series Convertible (E31), Jaguar XJS Convertible, and Aston Martin V8 Vantage Volante.

Design:

Iconic 'double-cowl' dashboard design, aerodynamic styling, integrated roll-over bar system, advanced retractable hardtop.

Technology:

Introduction of advanced safety features like the pop-up roll-bar, ABS, traction control (ASR), and sophisticated electronic engine management.

Value:

Provides detailed, dealership-level technical information essential for maintaining, troubleshooting, and repairing the 1994 R129 SL-Class, ensuring accuracy and efficiency for owners and technicians alike.

📋 Manual Details

Primary Coverage:

All Models & All Repairs A-Z for the 1994 Mercedes-Benz SL-Class (R129)

Engine Coverage:

3.2L Inline-6 (M104), 5.0L V8 (M119), 6.0L V8 AMG (M119)

Transmission Coverage:

4-speed Automatic (722.4), 5-speed Automatic (722.6 - early models)

Body Style Coverage:

Roadster (2-door convertible with retractable hardtop)

Estimated Page Count:

1000+

Type:

Factory Service Manual / Repair Manual

Language:

English

Format:

Print (likely spiral-bound or perfect-bound)

📖 Manual Coverage

Engine Mechanical:

Engine overhaul, cylinder head, pistons, crankshaft, camshafts, timing system, lubrication system, cooling system, fuel injection system (Bosch KE-Jetronic/LH-Jetronic), emission control systems.

Engine Electrical:

Ignition system, starting system, charging system, engine control unit (ECU) diagnostics and testing, sensors, actuators, wiring diagrams.

Transmission:

Automatic transmission overhaul, diagnosis, fluid and filter replacement, hydraulic systems, electronic controls.

Drivetrain:

Driveshafts, universal joints, differential, axle shafts.

Suspension:

Front and rear suspension systems, springs, shock absorbers (including self-leveling suspension if applicable), control arms, bushings, wheel alignment specifications.

Steering:

Power steering system, steering gear, steering column, hydraulic pump, linkages, diagnosis and repair.

Brakes:

Hydraulic system, anti-lock braking system (ABS), brake calipers, rotors, pads, master cylinder, brake lines, parking brake, diagnosis and repair.

Electrical System:

12V electrical system, battery, alternator, starter, lighting, fuses, relays, body control modules, multiplexed systems (if applicable), complete wiring schematics.

Climate Control:

Air conditioning system, heater, climate control unit (manual or automatic), refrigerant handling, diagnosis and repair.

Body:

Body panel repair, corrosion protection, doors, hood, trunk, convertible top mechanism (hydraulic and electrical), interior trim, glass replacement.

Convertible Top:

Hydraulic system, actuators, seals, controls, maintenance and repair of the power-operated retractable hardtop.

Restraint Systems:

Airbag system (SRS) diagnosis and component replacement, seatbelt mechanisms.

Diagnostics:

Troubleshooting guides, diagnostic trouble codes (DTCs), OBD-I system information, sensor testing procedures, component testing.

Maintenance:

Scheduled maintenance intervals, oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt inspection and replacement.

Repair:

Step-by-step repair procedures for all major mechanical and electrical components, including engine rebuilds, transmission overhauls, brake system repairs, suspension and steering work, convertible top repairs.

Troubleshooting:

Systematic diagnostic procedures for identifying and resolving common and uncommon faults, fault code interpretation, wiring diagram analysis.

Component Replacement:

Detailed instructions for removing and installing all vehicle components, including engine, transmission, suspension arms, brake assemblies, electrical modules, interior and exterior trim.

Technical Specifications:

Torque specifications for all fasteners, clearances, timing marks, fluid capacities, electrical resistance values, diagnostic voltage readings.

Wheel Alignment:

Alignment angles (camber, caster, toe), procedures, and specifications.

Body Work:

Panel replacement, dent repair, rust treatment, sealing procedures.

Depth:

Comprehensive (A-Z, covering basic maintenance to complete engine and transmission rebuilds, advanced diagnostics, and bodywork).

Diagnostic Focus:

Detailed diagnostic flowcharts and component testing for electrical and mechanical systems, including engine management and ABS.

Rebuild Procedures:

Complete engine and transmission rebuild instructions with detailed component specifications and assembly sequences.

📊 Manual Specifications

Digital Format:

N/A (Indicated as a printed manual)

Print Quality:

High (Typically professional printing with clear diagrams and text)

Binding Type:

Likely spiral-bound or perfect-bound for durability and ease of use in a workshop environment.

Paper Type:

Durable, high-quality paper suitable for workshop conditions, often with glossy pages for diagrams.

⚙️ Engine Specifications

Engine Variant:

SL 320 (3.2L)

Engine Code:

M104.980

Engine Type:

3.2L Inline-6, DOHC, 24 Valves

Horsepower:

230 hp @ 5700 rpm

Torque:

220 lb-ft @ 4400 rpm

Fuel Delivery:

Bosch LH-Jetronic Fuel Injection

Fuel Type:

Premium Unleaded Gasoline

Sl500 Engine:

5.0L V8 (M119.970), 322 hp @ 5500 rpm, 339 lb-ft @ 3900 rpm, Bosch LH-Jetronic Fuel Injection

Sl60 Amg Engine:

6.0L V8 (M119.974), Approx. 375-380 hp, High-performance fuel injection and exhaust systems.

🔧 Transmission

Standard Transmission:

4-speed Automatic (722.4)

Optional Transmission:

5-speed Automatic (722.6 - introduced later in the R129 lifecycle, may be present on very late '94 models or early '95)

Shift Modes:

Comfort/Sport shift modes on some variants.

Transmission Fluid Type:

MB 236.7 (or equivalent Dexron II/III for 722.4); MB 236.10/236.12 for 722.6 (check manual for exact spec).

📐 Dimensions

Length:

Approx. 178.3 inches (4529 mm)

Width:

Approx. 70.2 inches (1783 mm)

Height:

Approx. 51.0 inches (1295 mm)

Wheelbase:

Approx. 98.8 inches (2509 mm)

Curb Weight:

Approx. 3700-4000 lbs (1680-1815 kg), varies by engine and options.

Gross Vehicle Weight Rating:

Typically around 4700 lbs (2130 kg)

Towing Capacity:

Not Recommended/Not Available for standard models.

🛡️ Safety Features

NHTSA Ratings:

Specific NHTSA ratings for this era are not as comprehensive as modern standards, but the R129 was designed with advanced safety for its time.

ABS:

Standard Anti-lock Braking System (ABS)

Asr:

Optional or standard on some models: Acceleration Slip Regulation (ASR) / Traction Control

Airbags:

Driver and passenger airbags (SRS - Supplemental Restraint System)

Roll Over Protection:

Automatic deployable roll-over bar system integrated behind the seats.

Seatbelts:

Pretensioning seatbelts

💡 Technology Features

Audio System:

Factory-installed AM/FM/Cassette stereo, often with premium sound system options (e.g., Bose).

Display:

Analog gauges, digital odometer, climate control displays, radio display.

Cruise Control:

Standard electronic cruise control.

Traction Control:

ASR (Acceleration Slip Regulation) available on many models.

Cellular Technology:

No integrated smartphone connectivity or Bluetooth; optional (rare) early car phones may have been available.

Climate Control:

Automatic climate control (optional or standard depending on model/market) with dual-zone capability.

Seats:

Power-adjustable heated seats with memory function for driver and passenger.

Windows Mirrors:

Power windows, power-adjustable and heated side mirrors.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500-10,000 miles (12,000-16,000 km) or 12 months, whichever comes first, with synthetic oil.

Major Service:

Major services (e.g., spark plugs, transmission service) recommended around 30,000-60,000 miles (48,000-96,000 km) depending on component and driving conditions.

Coolant Change:

Recommended every 2-3 years or as specified by MB coolant type.

Engine Oil Type:

SAE 0W-40 or 5W-40 Synthetic (e.g., MB 229.5, API SN/SM/SL or ACEA A3/B4). Check manual for precise 1994 specification.

Engine Oil Capacity:

Approx. 8.0-8.5 liters (8.5-9.0 US quarts) for 3.2L and 5.0L engines.

Coolant Type:

Mercedes-Benz Approved Antifreeze/Coolant (e.g., G05 based, typically blue or green).

Brake Fluid Type:

DOT 4 (or DOT 3 for some earlier applications - confirm with manual).

Power Steering Fluid:

MB 236.3 Power Steering Fluid (or Dexron III if specified).

Wiring Harness Conduit:

Degradation of wiring harness insulation and conduit in engine bay and around various sensors leading to electrical faults.

Convertible Top Hydraulics:

Leaking hydraulic lines, pump issues, or cylinder seals can affect convertible top operation.

Mass Air Flow Sensor:

Failure of the MAF sensor (especially on M104 engines) can cause rough running and poor performance.

Idle Control Valve:

Issues with the idle control valve can lead to unstable idling or stalling.

Rust:

While generally well-protected, rust can occur in wheel wells, rocker panels, and around the windshield seal on older examples.

Ignition Modules:

Failure of the ignition control module (EZL) or coil packs.

📚 Vehicle History

Heritage:

Mercedes-Benz has a long-standing reputation for building robust, luxurious, and technologically advanced vehicles, particularly in the SL ('Sport Leicht' or 'Sport Light') lineage.

R129 Introduction:

The R129 generation debuted in 1989 as a successor to the highly successful R107 SL. It represented a significant leap forward in design, engineering, and safety.

R129 Key Updates:

Facelifted models arrived in 1995 with engine upgrades (e.g., M119 V8 to 5.0L 32 valve, introduction of the SL 320 with 24 valve M104 engine), revised styling, and new features.

1994 Positioning:

The 1994 model year falls within the pre-facelift R129 period, offering the classic R129 styling and powertrain options available before the 1995 updates.

Production Years:

1989-2001

Manufacturing Location:

Bremen, Germany

🏆 Awards & Recognition

Road And Track:

Frequently cited by automotive publications like Road & Track for its performance, handling, and luxury over its production run.

Consumer Reports:

While specific year awards vary, Mercedes-Benz vehicles from this era generally received positive marks for build quality and comfort, though maintenance costs were noted.

Safety Standards:

Designed to meet and exceed all applicable safety and emissions standards for North America and European markets for 1994.