🏷️ Basic Information

Make:

Mercedes-Benz

Model:

SLK320

Year:

2004

Chassis Code:

R171

👋 Introduction

Vehicle Segment:

Compact Sports Car / Roadster

Target Audience:

Enthusiasts seeking a premium, stylish, and sporty convertible experience.

Key Competitors:

BMW Z4, Audi TT Roadster, Porsche Boxster, Chevrolet Corvette (lower trims)

Convertible System:

Vario-Roof retractable hardtop, offering coupe-like security and convertible freedom.

Design Philosophy:

Aggressive styling, driver-focused cockpit, premium materials, and advanced technology for its class.

📋 Manual Details

Primary Coverage:

Service and Repair

Additional Coverage:

Maintenance, Diagnostics, Troubleshooting, Wiring Diagrams, Specifications

Target User:

Professional Technicians and Enthusiast DIYers

Estimated Pages:

1500+

Type:

Factory Service Manual (FSM) / Workshop Manual

License Status:

Officially Licensed

Language:

English

Format:

Software (likely PDF or proprietary application)

📖 Manual Coverage

Powertrain:

Engine (M112 V6), Transmission (5G-TRONIC Automatic), Differential

Chassis:

Suspension (Front: McPherson Strut, Rear: Multi-link), Steering, Brakes (Front: Ventilated Discs, Rear: Solid Discs), Wheels and Tires

Electrical:

Engine Control Unit (ECU), Body Control Module (BCM), Lighting, Instrumentation, Audio System, Climate Control, Power Accessories, SRS (Airbag) System, CAN Bus Communication

Body And Trim:

Exterior Body Panels, Interior Trim, Convertible Top System (Vario-Roof), Doors, Windows, Seats

Routine Maintenance:

Oil and Filter Change, Air Filter Replacement, Spark Plug Replacement, Fluid Level Checks and Top-offs, Brake Pad/Rotor Replacement, Tire Rotation

Engine Repair:

Timing Belt/Chain Inspection (though M112 is chain-driven), Cylinder Head Overhaul, Piston/Ring Replacement, Seal Replacement, Cooling System Service

Transmission Repair:

Fluid and Filter Service, Valve Body Diagnostics, Seal Replacements, Torque Converter Service

Suspension And Steering:

Shock/Strut Replacement, Control Arm Bushing Replacement, Tie Rod End Replacement, Power Steering System Service

Brake System:

Brake Fluid Flush, Caliper Rebuild, ABS/ESP System Diagnostics and Repair

Electrical Diagnostics:

Wiring Diagram Interpretation, Component Testing, Sensor Diagnosis, ECU Reprogramming/Adaptation (where applicable)

Convertible Top:

Hydraulic System Service, Actuator Replacement, Sensor Calibration, Weatherstripping Maintenance

Diagnostic Codes:

P-codes and manufacturer-specific OBD-II codes with descriptions and troubleshooting steps.

Diagnostic Capabilities:

Advanced fault code reading and interpretation, live data streaming (requires compatible diagnostic tool), component activation tests

Rebuild Procedures:

Detailed specifications and procedures for major component overhauls (engine, transmission)

Troubleshooting Guides:

Systematic diagnostic flowcharts for common and uncommon issues

Wiring Diagrams:

Comprehensive, system-by-system wiring diagrams included, crucial for electrical troubleshooting.

📊 Manual Specifications

Digital Format:

Proprietary Software / Searchable PDF

Digital Quality:

High-resolution diagrams and text, printable pages

Digital Format Notes:

Digital delivery allows for instant access and search functionality.

Digital Medium:

Delivered electronically via download.

⚙️ Engine Specifications

Engine Code:

M112 E32 ML

Configuration:

3.2L SOHC 18-valve V6 (90-degree bank angle)

Bore X Stroke:

89.9 mm x 84.0 mm

Compression Ratio:

10.0:1

Horsepower:

215 hp @ 5750 rpm

Torque:

221 lb-ft @ 3000-4500 rpm

Induction:

Naturally Aspirated

Fuel Type:

Premium Unleaded Gasoline (91+ Octane)

Fuel Delivery:

Electronic Fuel Injection (EFI) with Sequential Multi-Port Fuel Injection (MPFI)

ECU Type:

Bosch Motronic ME 2.8 (or similar variant)

🔧 Transmission

Type:

5-speed Automatic (5G-TRONIC, 722.6)

Manual Override:

TouchShift (Driver selectable manual shifting)

Availability:

Not available for SLK320 in 2004; a 6-speed manual was offered on other SLK models/years.

Fluid Type:

MB Spec 236.10 ATF (e.g., Mobil ATF 220, Pentosin ATF 1)

Fluid Capacity:

Approximately 7.5-8.0 liters (dry fill)

📐 Dimensions

Length:

157.2 in (3993 mm)

Width:

69.5 in (1765 mm)

Height:

50.7 in (1288 mm)

Wheelbase:

81.5 in (2070 mm)

Front Track:

59.3 in (1506 mm)

Rear Track:

58.7 in (1491 mm)

Curb Weight:

3285 lbs (1490 kg)

Gross Vehicle Weight Rating:

3968 lbs (1800 kg)

Trunk Volume Top Up:

8.5 cu ft (240 L)

Trunk Volume Top Down:

4.2 cu ft (119 L)

🛡️ Safety Features

NHTSA Front Impact:

5-Star (for driver and passenger, typical for the era)

IIHS Side Impact:

Good (typical for Mercedes-Benz of this period)

ABS:

Standard Anti-lock Braking System

Esp:

Standard Electronic Stability Program (ESP)

Traction Control:

Standard ASR (Acceleration Slip Regulation)

Airbags:

Driver, Passenger, Side-Impact (Thorax) Airbags

Rollover Protection:

Pop-up roll bars integrated behind the headrests

Seatbelts:

Pretensioning Seatbelts with Force Limiters

💡 Technology Features

Head Unit:

COMAND APS (optional) or Audio 20 with CD player

Navigation:

Available with COMAND APS navigation system

Audio Features:

Optional Bose sound system, optional CD changer

Cruise Control:

Standard Cruise Control

Parking Assist:

Optional PARKTRONIC parking sensors

Bluetooth:

Optional Bluetooth telephone module

Climate Control:

Standard THERMATIC automatic climate control (optional THERMOTRONIC dual-zone)

Seats:

Standard heated sport seats, optional multi-contour seats, optional power adjustment with memory

🔧 Maintenance

Oil And Filter Change:

Flexible Service System (ASSYST) - typically every 10,000 miles or 12 months, whichever comes first, or as indicated by the onboard computer.

Spark Plug Replacement:

Approximately 100,000 miles (original equipment typically iridium)

Transmission Service:

Fluid and filter change recommended every 60,000 miles or as per ASSYST.

Coolant Flush:

Every 30,000 miles or 2 years.

Engine Oil:

SAE 0W-40 or 5W-40, MB Approved 229.5 Specification

Engine Oil Capacity:

8.0 Liters (with filter)

Coolant:

Mercedes-Benz Approved Antifreeze/Coolant (e.g., MB 325.0 or 326.0) - typically a 50/50 mix with distilled water

Brake Fluid:

DOT 4 Plus (MB Spec 331.0)

Convertible Top Hydraulics:

Leaking cylinders or pumps, sensor issues can cause the Vario-Roof to malfunction. Regular fluid checks and top-up are crucial.

Mass Air Flow Sensor:

Can become dirty, leading to rough idle, poor acceleration, and check engine light.

Crankshaft Position Sensor:

Failure can lead to no-start conditions or intermittent stalling.

Rear Main Seal:

Can develop leaks over time, requiring transmission removal for replacement.

Suspension Components:

Control arm bushings, ball joints, and tie rod ends can wear, causing steering looseness and noise.

📚 Vehicle History

Manufacturer:

Mercedes-Benz AG (DaimlerChrysler)

Establishment Date:

1926 (merger of Benz & Cie. and Daimler-Motoren-Gesellschaft)

R170 Predecessor:

The R171 replaced the R170 SLK generation.

R171 Introduction:

The R171 generation debuted for the 2004 model year.

Slk320 Positioning:

The SLK320 represented the mid-tier engine option for the R171 generation, below the supercharged SLK32 AMG.

Production Period:

2004-2008 (for R171 SLK320)

Manufacturing Plant:

Bremen, Germany

🏆 Awards & Recognition

Vehicle Awards General:

While specific awards for the 2004 SLK320 are hard to isolate, the R171 generation generally received positive reviews for its styling, performance, and advanced features. Mercedes-Benz consistently ranks high in customer satisfaction surveys for reliability and build quality.