2014 Mercedes-Benz SLK55 AMG

The 2014 Mercedes-Benz SLK55 AMG is a performance-oriented roadster featuring a hand-built 5.5-liter naturally aspirated V8 engine producing 415 horsepower and 398 lb-ft of torque. This engine is paired exclusively with a 7-speed automatic transmission (7G-TRONIC PLUS). While praised for its powerful engine, engaging driving dynamics, and luxurious interior, some owners have reported specific issues. Commonly liked are the raw power, exhaust note, and retractable hardtop. Common dislikes include the firm ride and dated infotainment system. Other engine options available on the SLK lineup include a 1.8-liter turbocharged four-cylinder and a 3.5-liter V6.

Engine

5.5L M152 V8

• Camshaft Adjuster/Magnet Failure
  • Description/Symptoms: Check engine light, rough idle, decreased performance. The camshaft adjuster magnets can fail, causing the camshaft timing to be incorrect.
  • Solution: Replacement of the faulty camshaft adjuster magnet(s).
  • Estimated Cost to Fix: $500 - $1000+
• Valve Lifter Noise
  • Description/Symptoms: Ticking or clicking noise from the engine, especially noticeable at idle or low speeds. This is often caused by worn or sticking hydraulic valve lifters.
  • Solution: Replacement of the affected valve lifters. In some cases, a more extensive repair may be needed if the camshaft is damaged.
  • Estimated Cost to Fix: $1000 - $4000+
• Oil Leaks
  • Description/Symptoms: Visible oil leaks from various engine seals and gaskets, such as the valve cover gaskets, oil pan gasket, or rear main seal.
  • Solution: Replacement of the leaking seals and gaskets.
  • Estimated Cost to Fix: $200 - $1500+ depending on the location and severity of the leak.

Transmission

7G-TRONIC PLUS (722.9)

• Rough or Delayed Shifting
  • Description/Symptoms: Harsh or jerky shifts, delayed engagement when shifting into drive or reverse, or slipping between gears. These issues can be caused by valve body problems, conductor plate failure, or low transmission fluid.
  • Solution: Diagnostic testing to determine the cause, followed by repair or replacement of the valve body, conductor plate, or other faulty components. A transmission fluid flush may also be necessary.
  • Estimated Cost to Fix: $500 - $3000+
• Torque Converter Issues
  • Description/Symptoms: Shuddering or vibrations at low speeds, especially when accelerating from a stop. This can be caused by a failing torque converter.
  • Solution: Replacement of the torque converter.
  • Estimated Cost to Fix: $1500 - $3000+

Suspension

• Air Suspension Issues (If Equipped)
  • Description/Symptoms: Vehicle sagging on one or more corners, failure of the air compressor, or error messages on the dashboard.
  • Solution: Replacement of the faulty air struts, air compressor, or other components of the air suspension system.
  • Estimated Cost to Fix: $800 - $2000+ per strut, $500-$1500+ for the air compressor.

Electrical

• Battery Drain
  • Description/Symptoms: The battery drains quickly, especially if the car sits for an extended period. This can be due to a faulty component not shutting off properly.
  • Solution: Diagnostic testing to identify the source of the drain, followed by repair or replacement of the affected component.
  • Estimated Cost to Fix: $100 - $500+
• Sensor Failures (Crankshaft, Camshaft, etc.)
  • Description/Symptoms: Check engine light illuminated, rough running, stalling, or difficulty starting.
  • Solution: Diagnosis to identify the faulty sensor and replacement.
  • Estimated Cost to Fix: $200-$500+

Exterior

• Retractable Hardtop Malfunctions
  • Description/Symptoms: The retractable hardtop fails to open or close properly, makes unusual noises, or gets stuck. This can be caused by faulty hydraulic components, sensors, or mechanical linkages.
  • Solution: Diagnostic testing to identify the cause of the malfunction, followed by repair or replacement of the affected components.
  • Estimated Cost to Fix: $500 - $3000+ depending on the complexity of the issue.

Interior

• COMAND System Issues
  • Description/Symptoms: The COMAND infotainment system freezes, crashes, or experiences other software glitches.
  • Solution: Software update or replacement of the COMAND unit.
  • Estimated Cost to Fix: $200 - $2000+

Summary

The 2014 Mercedes-Benz SLK55 AMG, while a desirable performance roadster, can be prone to some issues, especially with its engine and transmission. The engine issues can range from relatively minor oil leaks to more serious problems like camshaft adjuster or valve lifter failures. The transmission can also exhibit issues, ranging from rough shifting to internal failures, necessitating costly repairs. Electrical gremlins and retractable hardtop issues are also common complaints. Overall, potential buyers should be aware of these potential issues and factor in maintenance and repair costs when considering purchasing one.