🏷️ Basic Information

Make:

Mercedes-Benz

Model:

SLK

Model Code:

R172

Model Year:

2018

Generation:

Third Generation (R172)

Chassis Code:

R172

👋 Introduction

Market Position:

A premium compact roadster positioned as an entry-level luxury sports car, offering a blend of performance, comfort, and advanced technology. The R172 SLK is known for its distinctive 'Vario-Roof' retractable hardtop.

Target Audience:

Enthusiast owners, independent repair shops, and DIY mechanics seeking professional-grade diagnostic and repair information for their 2018 Mercedes-Benz SLK (R172).

Competitive Analysis:

Competes with vehicles like the Audi TT Roadster, BMW Z4, and Porsche Boxster, offering a sophisticated driving experience with Mercedes-Benz's signature build quality and engineering. The 2018 model year falls within the facelifted R172 generation, which introduced updated styling and technology.

Key Features:

Electrically operated retractable hardtop (Vario-Roof), rear-wheel drive, advanced safety features, premium interior appointments, and optional performance enhancements. The manual provides specific details for all these aspects.

📋 Manual Details

Coverage Areas:

All Models & All Repairs A-Z for the 2018 Mercedes-Benz SLK (R172)

Page Count:

Not Specified (Comprehensive Digital Manual)

Manual Type:

Factory Service and Repair Manual

Language:

English

Format:

PDF

Format Features:

Searchable text, printable pages, zoomable diagrams and illustrations, hyperlinked sections for easy navigation.

Requirements:

Adobe PDF Reader and Winzip (or equivalent decompression utility).

📖 Manual Coverage

Systems Covered:

Maintenance, Engine, Control System, Mechanical, Fuel Service, Emission Control, Intake, Exhaust, Cooling, Lubrication, Ignition, Starting, Charging, Automatic Transmission, Clutch, Manual Transmission, Transfer Case, Propeller Shaft, Drive Shaft, Differential, Axle, Suspension, Tire & Wheel, Brake Control, Brakes, Parking Brake, Steering Column, Power Steering, Air Conditioning, Supplemental Restraint System (SRS), Seat Belts, Engine Immobilizer, Cruise Control, Wiper & Washer, Door Locks, Meter, Audio/Visual, Horn, Windshield/Glass/Mirror, Instrument Panel, Seats, Engine Hood/Doors, Exterior & Interior, Electrical, Multiplex/CAN Communication, Body Control Modules, Powertrain Control Modules, Chassis Control Modules, Diagnostics, Troubleshooting.

Systems Covered Additional:

Body Electrical, Chassis Electrical, Powertrain Control, Climate Control, Infotainment, Advanced Driver-Assistance Systems (ADAS), Vario-Roof control unit, lighting systems, door control modules, keyless-go systems.

Systems Covered Electrical:

Complete wiring schematics for all major systems, including engine control, body control, chassis control, lighting, infotainment, climate control, power accessories, and CAN bus communication network.

Procedures Included:

Step-by-step repair instructions, diagnostic procedures, routine maintenance schedules, component removal and installation, wiring schematic interpretation, troubleshooting flowcharts, fluid specifications and capacities, torque specifications, system adjustments, calibration procedures.

Procedures Included Additional:

Component testing, diagnostic trouble code (DTC) interpretation and clearing, wiring harness repair, sensor replacement and calibration, control module programming and configuration, system bleeding procedures (e.g., brake system), wheel alignment specifications.

Procedures Included Body:

Body panel alignment, door and lid adjustments, convertible top mechanism servicing, interior trim panel removal and installation, exterior trim component replacement, paint repair guidelines (briefly), and corrosion protection.

Technical Depth:

Factory-level, detailed diagnostics, repair, service, and maintenance procedures. Equivalent to dealership technician manuals. Covers everything from basic fluid checks to complex electronic system diagnostics and driveline overhauls.

Technical Depth Additional:

Includes detailed torque specifications for all critical fasteners, tightening sequences, gasket and seal replacement procedures, bearing clearances, and gear train specifications. Covers electronic component diagnostics using STAR DIAGNOSIS (DAS) or equivalent methods.

📊 Manual Specifications

File Format:

PDF (Portable Document Format)

Compatibility:

Windows Vista 32/64, XP, ME, 98, NT, 2000, and Mac OS.

Print Quality:

High Resolution, suitable for printing with clear diagrams and text. Enlargement capability for detailed viewing.

Binding Type:

Digital (PDF)

Paper Type:

N/A (Digital Format, printable onto any paper type)

⚙️ Engine Specifications

Primary Engine:

Likely the M274 DE 20 AL 2.0L Inline-4 Turbocharged (for SLK 200/300 variants) or potentially the M276 DE35 V6 Twin-Turbocharged for AMG variants (e.g., SLC 43, which replaced the SLK 55). The exact engine will depend on the specific model variant covered, but the manual is comprehensive.

Performance:

2.0L Turbo I4: Approx. 181-241 hp, 200-273 lb-ft torque. 3.0L Twin-Turbo V6 (SLC 43): Approx. 362 hp, 384 lb-ft torque. Manual provides exact figures for all covered engine options.

Fuel System:

Direct Injection (Bosch MED 17.7/17.8/17.9 ECUs likely), Electronic Fuel Injection (EFI) with high-pressure fuel pump.

Engine Codes:

M274 DE20 AL (2.0L Turbo I4), M276 DE30 LA (3.0L Twin-Turbo V6 for AMG SLC 43). Manual covers specific codes and their variations.

Ignition System:

Direct ignition system with individual coil-on-plug units. Manual details spark plug types (e.g., NGK LFR6AIX-11S or equivalent), gap specifications, and replacement intervals.

Cooling System:

Engine coolant thermostat controlled, electric cooling fan, auxiliary electric water pump (on some models). Manual covers coolant circulation, pressure testing, and component replacement (pump, thermostat, radiator).

Engine Type:

Inline-4 Turbocharged (M274) or V6 Twin-Turbocharged (M276 AMG). Manual covers both, with specific sections for each engine variant.

🔧 Transmission

Standard:

7-speed automatic transmission (7G-TRONIC PLUS, 722.9 series) for most models. AMG variants may use the AMG SPEEDSHIFT PLUS 9G-TRONIC.

Optional:

Manual transmission was phased out for the R172 in many markets, but the manual likely covers diagnostic and service procedures for both automatic and any remaining manual transmission variants if applicable.

Features:

Paddle shifters, Sport/Economy modes, Adaptive Electronic Control. Manual details internal components, hydraulic control units, and solenoid operation.

Transmission Codes:

722.9 (7G-TRONIC PLUS), 725.0 (9G-TRONIC - for AMG SLC 43).

Transmission Type:

Automatic (7-speed or 9-speed for AMG) with manual shifting modes.

📐 Dimensions

Exterior:

Length: Approx. 160.5 in (4075 mm), Width: Approx. 70.5 in (1791 mm), Height: Approx. 52.0 in (1320 mm), Wheelbase: Approx. 94.5 in (2400 mm). Specifics may vary slightly by engine option.

Interior:

2-seater configuration. Interior dimensions focus on ergonomics, seating adjustments, and cabin comfort. Manual covers seat adjustment mechanisms, interior trim removal, and HVAC system.

Cargo:

Trunk Volume: Approx. 6.5 - 10.1 cu ft (184 - 285 Liters), depending on roof position. Manual provides details on the retractable roof mechanism and cargo area components.

Weights:

Curb Weight: Approx. 3,200 - 3,500 lbs (1450 - 1600 kg), depending on engine and options. Manual includes Gross Vehicle Weight Rating (GVWR) and axle load capacities.

Wheel Bolt Pattern:

5x112mm

Wheel Offset:

Typically ET 35-50, depending on wheel size and front/rear axle. Manual provides specific OEM wheel fitment data.

Tire Sizes:

Common sizes include 225/40 R18 (front) and 245/35 R18 (rear) for standard models. AMG variants may use larger or wider tires. Manual lists all approved tire sizes and pressures.

🛡️ Safety Features

Ratings:

While specific NHTSA/IIHS ratings for the 2018 model year may require verification, Mercedes-Benz vehicles are consistently high performers. The R172 would have been designed to meet or exceed global safety standards of its time. Manual covers airbags, seatbelt pre-tensioners, and chassis integrity.

Active Features:

Anti-lock Braking System (ABS), Electronic Stability Program (ESP), Traction Control System (TCS), Adaptive Brake Assist, PRE-SAFE® system, Tire Pressure Monitoring System (TPMS). Manual provides diagnostic procedures for all these systems.

Passive Features:

Front airbags, side airbags, knee airbags (driver), seatbelt pretensioners, rollover protection system (pop-up bars), reinforced A-pillars. Manual details airbag module replacement, SRS system diagnostics, and seat belt assembly servicing.

💡 Technology Features

Infotainment:

COMMAND infotainment system with 7-inch display, Bluetooth connectivity, USB interface, optional navigation, digital radio (DAB). Manual covers system diagnostics, component replacement, and software updates.

Driver Assistance:

Optional Driver Assistance Package could include Active Parking Assist, Adaptive Cruise Control (DISTRONIC PLUS), Blind Spot Assist, Lane Keeping Assist. Manual provides detailed information on sensor calibration and system troubleshooting.

Connectivity:

Bluetooth telephony and audio streaming, USB ports for media and charging. Mercedes-Benz Link (e.g., for smartphones) may be supported. Manual details the electronic modules and communication protocols involved.

🔧 Maintenance

Service Intervals:

Flexible service intervals managed by the 'ASSYST PLUS' system, typically around 10,000-15,000 miles or 12 months for oil changes. Major services (e.g., spark plugs, transmission fluid) at higher mileages, e.g., 40,000-60,000 miles. Manual provides detailed service schedules and reset procedures.

Brake Fluid Interval:

Typically every 2 years, regardless of mileage.

Air Filter Interval:

Approximately every 30,000 miles or as indicated by the ASSYST system. Manual provides replacement procedure.

Cabin Filter Interval:

Annually or every 10,000-15,000 miles. Manual covers replacement of dust/pollen filters.

Fluid Specifications:

Engine Oil: MB 229.51 or MB 229.52 (e.g., 0W-30, 5W-30 synthetic). Automatic Transmission Fluid: MB 236.14 (e.g., ATF 7G-TRONIC). Coolant: MB 325.0 or 326.0 (G48 blue). Brake Fluid: DOT 4 Plus (MB 331.0). Power Steering Fluid: MB 236.3 (e.g., CHF 11S) or integrated electric power steering (EPS) with no fluid.

Coolant Capacity:

Approx. 7.0 - 8.0 Liters (1.8 - 2.1 Gallons). Manual provides exact capacity based on engine variant.

Engine Oil Capacity:

Approx. 5.5 - 6.5 Liters (5.8 - 6.9 Quarts) for 2.0L Turbo I4. Manual provides exact capacity and dipstick/electronic level check procedure.

Brake Fluid Type:

DOT 4 Plus (MB Spec 331.0)

Known Issues:

Potential issues can include Vario-Roof mechanism faults (hydraulic leaks, sensor failures), ignition coil failures, oil leaks from the valve cover or oil filter housing, transmission control module (TCM) issues, and HVAC system component failures. The manual provides diagnostic and repair procedures for all these common concerns.

📚 Vehicle History

Brand Heritage:

Mercedes-Benz boasts a long history of innovation in automotive engineering, luxury, and performance, dating back to the invention of the automobile. The SLK nameplate, introduced in 1996, represents a modern interpretation of the classic two-seat roadster.

Model Evolution:

The R172 generation (2011-2020) succeeded the R171. The 2016 facelift saw the SLK renamed to SLC, though this manual specifies the 2018 model as SLK (R172), indicating it covers the platform prior to or during the rebranding period. Key changes included exterior styling updates, interior trim revisions, and powertrain enhancements, including the introduction of the AMG SLC 43.

Production:

The R172 SLK/SLC was primarily manufactured at the Mercedes-Benz plant in Bremen, Germany. Production for the R172 ran from 2011 to 2020.

Model Designation:

The R172 SLK was officially renamed SLC for the 2016 model year facelift, but this manual specifies it as SLK (R172) for 2018, likely indicating it covers the platform as it transitioned or includes pre-facelift information as well if it applies to the 2018 production timeframe of the R172 chassis.

🏆 Awards & Recognition

Recognitions:

While specific awards for the 2018 model might be limited, previous generations of the SLK have received accolades for design and performance from various automotive publications. The R172 platform is recognized for its sophisticated engineering and driving dynamics.

Ratings:

Consistent high ratings for build quality, interior luxury, and driving experience in automotive reviews. The manual implicitly supports the maintenance of these high standards.