🏷️ Basic Information

Make:

Mercedes-Benz

Model:

300 SL

Model Code:

R129

Years Covered:

1990-1993

Engine Code General:

M104

👋 Introduction

Positioning:

The Mercedes-Benz 300 SL (R129) represented the pinnacle of luxury roadster engineering and performance in its era, competing with high-end European sports cars.

Competitors:

Key competitors included models like the Porsche 911, BMW 8 Series convertible, and Jaguar XJS.

Vehicle Features:

Sophisticated multi-link rear suspension, advanced electronic control systems (e.g., optional ADS and 4MATIC), powerful inline-six engines, and the signature retractable hardtop (for some models, though the R129 featured a folding soft top and optional hardtop).

Value:

Provides access to the same authoritative repair information utilized by authorized Mercedes-Benz dealerships, enabling accurate and efficient maintenance and repair.

📋 Manual Details

Overall Coverage:

Comprehensive factory service and repair for 1990-1993 Mercedes-Benz 300 SL (R129 chassis).

Specific Years Covered:

1990, 1991, 1992, 1993

Estimated Page Count:

Estimated to be extensive, typical for full factory service manuals covering multiple model years and systems. Exact count not provided, but indicative of comprehensive coverage.

Type:

Factory Service and Repair Manual

Language:

English

Format:

PDF Download

File Quality:

High-quality, searchable, bookmarked, non-scanned real files.

📖 Manual Coverage

Engine Management:

Fuel injection timing, idle speed adjustment, spark plug checks and replacement, oxygen sensor replacement, intake/exhaust manifold seating, engine stop adjustment, engine mount bolt re-torque.

Cooling System:

Coolant level and antifreeze protection checks, cooling and heating system inspection, coolant replacement.

Drivetrain:

Manual transmission oil change, checking/correcting oil level. Automatic transmission fluid and filter change, checking/correcting fluid level. Transfer case fluid change, checking/correcting fluid level. Clutch system fluid level checking/correcting, clutch system inspection, clutch disk wear inspection.

Suspension:

Suspension and body structure inspection, self-leveling suspension inspection, Level Control (ADS), 4MATIC fluid level checks, front axle oil level check, front axle ball joint checks (including with special tool), rear axle oil change, rear axle oil level check, rear axle mount limiting stop adjustment.

Brakes:

Brake fluid level check, brake line inspection, brake pad and disk thickness check, brake disk inspection and cleaning, parking brake cable inspection, parking brake adjustment, brake fluid replacement, brake test, parking brake check.

Steering:

Power steering fluid level check, steering play check, steering bolt re-tightening.

Electrical:

Battery fluid level check, warning and indicator lamp checks, headlamp and exterior lamp inspection.

Body And Chassis:

Water leakage and corrosion inspection, wheel inspection and rotation, tire inspection and pressure correction, wheel bolt tightening, drive shaft flexible coupling inspection, exhaust flange re-tightening, exhaust system connection re-tightening, body paint damage inspection, door hinge lubrication, door lock lubrication, hood lubrication, lower noise encapsulation panel removal/installation, engine compartment lower panel removal/installation, sunroof rail cleaning and greasing, soft top locking tab check.

Climate Control:

Windshield washer fluid level check, AC refrigerant charge check/correction, dust filter replacement, active charcoal filter replacement, recirculating air filter replacement, heating and ventilation system filters.

Fuel System Components:

Fuel filter replacement, fuel system condition checks.

Maintenance Procedures:

Engine oil and filter change, valve clearance adjustment/checking, V-belt and poly V-belt checking and tensioning, air filter replacement, fuel filter replacement, transmission fluid changes, brake fluid flush, differential fluid changes, power steering fluid top-off, battery maintenance, lubrication points (hinges, locks, hood, sunroof).

Diagnostic Procedures:

Component condition inspection, lines and hoses inspection, suspension and body structure inspection, water leakage and corrosion inspection, idle speed checking/adjusting, injection timing checks/adjustments, steering play assessment, warning lamp troubleshooting.

Repair Procedures:

Replacement of spark plugs, oxygen sensor, fuel filter, transmission filters, brake pads, brake fluid, clutch system components, self-leveling suspension components, and various seals/gaskets implied by fluid level checks.

Adjustment Procedures:

Valve clearance, idle speed, injection timing, parking brake, rear axle limiting stops, engine mount bolts.

Depth:

Factory-level detail, suitable for professional technicians and advanced DIY enthusiasts. Covers routine maintenance through to component replacement and adjustments.

📊 Manual Specifications

Format:

PDF

Printability:

Printable pages. User can print specific sections or the entire manual.

Binding:

Digital Download (no physical binding).

Paper Type:

Not applicable for digital download.

Features:

Fully bookmarked and searchable PDF for quick information retrieval.

⚙️ Engine Specifications

Engine Type:

Inline 6-cylinder, DOHC

Engine Displacement:

3.0 Liters (2960 cc)

Engine Code:

M104.980

Horsepower:

Approximately 228 hp (170 kW) at 6,000 rpm

Torque:

Approximately 200 lb-ft (271 Nm) at 4,400 rpm

Fuel Delivery:

Bosch KE-Jetronic mechanical-electronic fuel injection with Electronic Control Unit (ECU) for ignition and injection timing.

Spark Plugs:

Refer to manual for specific type and gap. Likely Bosch Super Plus or similar. Replacement intervals typically 30,000 miles.

Oil Type:

Refer to manual for specific viscosity and MB approval. Typically SAE 5W-40 or 10W-40 synthetic or semi-synthetic.

Oil Capacity:

Approximately 7.5 liters (including filter).

Air Filter:

Paper element, metal reinforced. Cleaning and replacement procedures detailed.

Coolant:

Ethylene glycol based, 50/50 mix with distilled water. MB approval 325.0 or equivalent. Check freeze protection. Replacement interval typically every 2-3 years.

🔧 Transmission

Transmission Type:

4-speed Automatic (722.3xx series)

Transmission Type:

5-speed Manual (G30)

Automatic Transmission Fluid:

MB 236.7 specification. Typically Dexron II or equivalent. Check and correct fluid level with engine running and in Park. Fluid and filter change typically every 30,000-50,000 miles.

Manual Transmission Oil:

Refer to manual for specific MB approval and viscosity. Typically SAE 75W-90 or 80W-90 gear oil. Oil change intervals typically 30,000-50,000 miles.

Transfer Case Oil:

Applicable to 4MATIC models. Refer to manual for specific MB approval and viscosity. Fluid change intervals typically 30,000-50,000 miles.

📐 Dimensions

Length:

Approx. 4,499 mm (177.1 in)

Width:

Approx. 1,796 mm (70.7 in)

Height:

Approx. 1,308 mm (51.5 in)

Curb Weight:

Approx. 1,600-1,700 kg (3,527-3,748 lbs), varies by options.

🛡️ Safety Features

Crash Test Results:

Not specifically rated under modern standards like NHTSA or Euro NCAP for this era. However, Mercedes-Benz vehicles of this period were known for robust construction and advanced safety features for their time.

Anti Lock Braking System:

Standard ABS

Traction Control:

Optional ASR (Anti-Slip Regulation) available on some models, particularly 4MATIC.

Airbags:

Standard driver airbag. Passenger airbag introduced later in the R129 production run (typically from MY1994 onwards, but potentially available earlier as an option).

Rollover Protection:

Automatic rollover bars deployed behind the headrests in the event of a potential rollover.

Seat Belts:

Three-point inertia-reel seat belts, belt height adjusters.

💡 Technology Features

Audio System:

Factory premium sound systems were available, often with cassette players. Cleaning tone head for cassette deck is covered.

Adaptive Dampening System:

Optional ADS (Automatic Damping System) for adjustable ride stiffness based on driving conditions.

All Wheel Drive:

Optional 4MATIC all-wheel-drive system available, providing enhanced traction in various conditions.

Antenna:

Power antenna mast with cleaning and greasing procedures detailed.

Cabin Filters:

Dust filter, active charcoal filter, and recirculating air filter for heating and ventilation system are replaceable.

🔧 Maintenance

Oil Change Interval:

Typically every 7,500 to 10,000 miles or 12 months, whichever comes first. Consult the manual for precise recommendations based on driving conditions.

Transmission Service Interval:

Automatic transmission fluid and filter change recommended every 30,000 to 50,000 miles. Manual transmission fluid change similar interval.

Coolant Change Interval:

Typically every 2-3 years or 30,000 miles. Check freeze protection annually.

Brake Fluid Flush Interval:

Every 2 years regardless of mileage, as brake fluid absorbs moisture.

Power Steering Fluid:

MB 236.3 specification hydraulic fluid. Check level with engine warm and running.

Hydraulic Top Fluid:

System for soft top operation uses specific hydraulic fluid. Refer to manual for MB approval and part number.

Common Wear Items:

Age-related degradation of rubber hoses and seals (cooling, vacuum, hydraulic systems), potential issues with the soft top hydraulic system, wear in suspension bushings, and older electronic components can be prone to failure.

Specific Concerns:

Wiring harness insulation can become brittle over time. Ball joint wear. Corrosion in certain areas if not properly maintained.

📚 Vehicle History

Heritage:

Mercedes-Benz has a long-standing heritage of luxury, performance, and engineering innovation, particularly in the sports car segment with models like the original 300 SL 'Gullwing'.

R129 Introduction:

The R129 generation replaced the R107 SL. It debuted in 1989 for the 1990 model year and was a significant modernization in terms of design, technology, and safety.

300 Sl Positioning:

The 300 SL was the entry-level model in the R129 range during these early years, powered by Mercedes' new M104 inline-six engine.

Manufacturing Location:

Bremen, Germany

🏆 Awards & Recognition

Design Awards:

While specific awards for the 1990-1993 300 SL might not be readily documented, the R129 SL generation is widely acclaimed for its timeless design by Bruno Sacco.

Expert Reviews:

Consistently praised by automotive journalists of the era for its blend of performance, luxury, build quality, and technological advancements. Recognized as a benchmark luxury sports convertible.

Oem Certification:

This manual represents OEM certification standard, being the factory service manual used by authorized dealers.