2018 Mercedes-Benz CLS400

The 2018 Mercedes-Benz CLS400 is a stylish four-door coupe known for its sleek design and luxurious features. The CLS400 is equipped with a 3.0-liter twin-turbo V6 engine producing 329 horsepower and 354 lb-ft of torque. Other engine options included the CLS550 with a 4.7L V8 and the AMG CLS63 with a 5.5L V8. All engine options were mated to a 9G-TRONIC 9-speed automatic transmission. Owners generally appreciate the car’s elegant styling and comfortable ride, but some have noted issues with electronics and occasional mechanical problems.

Engine

3.0L Twin-Turbo V6 (M276)

• Oil Leaks
  • Description/Symptoms: Oil leaks can occur from various points, including the valve cover gaskets and the oil filter housing. Symptoms include visible oil drips, burning oil smell, and low oil levels.
  • Solution: Replace the faulty gaskets or the entire oil filter housing.
  • Estimated Cost to Fix: $200 - $800+
  • Recalls: None Found
• Fuel Injector Issues
  • Description/Symptoms: Misfires, rough idling, poor fuel economy, and potential check engine light illumination.
  • Solution: Replacement of faulty fuel injectors.
  • Estimated Cost to Fix: $400 - $1200+
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic (725.0)

• Rough Shifting/Hesitation
  • Description/Symptoms: Some owners have reported rough or delayed shifts, especially when shifting between certain gears. Hesitation when accelerating from a stop has also been noted.
  • Solution: Transmission fluid flush and software update. In more severe cases, valve body replacement or transmission rebuild may be necessary.
  • Estimated Cost to Fix: $300 (fluid flush) - $4000+ (rebuild)
  • Recalls: None Found
• Torque Converter Issues
  • Description/Symptoms: Shuddering during light acceleration, especially at lower speeds. Can also cause unusual noises and vibrations.
  • Solution: Replacement of the torque converter.
  • Estimated Cost to Fix: $1500 - $3000+
  • Recalls: None Found

Suspension

• Air Suspension Problems (If Equipped)
  • Description/Symptoms: The Airmatic suspension system can experience issues such as sagging, uneven ride height, or complete failure. This is often caused by leaks in the air struts or a failing compressor.
  • Solution: Replacement of the affected air struts or the air suspension compressor.
  • Estimated Cost to Fix: $800 - $2000+ per strut, $500 - $1500+ for the compressor
  • Recalls: None Found

Electrical

• Battery Drain Issues
  • Description/Symptoms: The battery draining quickly, especially if the car sits for a few days. This can be caused by a faulty module or a parasitic draw.
  • Solution: Diagnosis of the parasitic draw and replacement of the faulty component.
  • Estimated Cost to Fix: $150 - $1000+ depending on the component
  • Recalls: None Found
• Infotainment System Glitches
  • Description/Symptoms: Freezing, crashing, or unresponsive touchscreen. Bluetooth connectivity problems can also occur.
  • Solution: Software update, or in some cases, replacement of the infotainment unit.
  • Estimated Cost to Fix: $0 (software update) - $2000+ (unit replacement)
  • Recalls: None Found

Exterior

• Sensor Failures (Parking Sensors, Blind Spot Monitoring)
  • Description/Symptoms: Malfunctioning parking sensors or blind spot monitoring systems. Often indicated by error messages or failure to activate.
  • Solution: Replacement of the faulty sensor(s).
  • Estimated Cost to Fix: $200 - $500+ per sensor
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroof may fail to open or close properly, or make unusual noises. The motor or the track mechanism may be faulty.
  • Solution: Repair or replacement of the sunroof motor or track.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found

Summary

The 2018 Mercedes-Benz CLS400 is generally a reliable vehicle, but owners have reported issues primarily with the engine, transmission, electrical system, and suspension (if equipped with Airmatic). Engine oil leaks and transmission rough shifting are common complaints. Electrical glitches and sensor failures are also prevalent. Air suspension issues can be costly to repair. Overall, while some issues are relatively minor and inexpensive to fix, others can be more severe and result in significant repair costs. Potential buyers should be aware of these common problems and factor them into their purchasing decision.