2019 Mercedes-Benz SL450

The 2019 Mercedes-Benz SL450 is a luxury roadster that combines performance with open-top enjoyment. The SL450 is powered by a 3.0-liter twin-turbo V6 engine producing 362 horsepower and 369 lb-ft of torque. A 9-speed automatic transmission is standard. Other engine options in the SL range include the more powerful SL550 with a 4.7L V8, and the AMG SL63 and SL65 with various iterations of a 6.0L V12. Owners often praise the SL450 for its comfortable ride, elegant interior, and powerful engine. Common criticisms include the somewhat dated infotainment system and limited rear storage space.

Engine

3.0L Twin-Turbo V6

• Oil Leaks from Turbocharger Oil Lines
  • Description/Symptoms: Oil leaks noticed under the vehicle or a burning oil smell. Visible oil residue around the turbochargers.
  • Solution: Replacement of the turbocharger oil lines.
  • Estimated Cost to Fix: $800 - $1500+
  • Recalls: None Found
• Camshaft Adjuster Solenoid Failure
  • Description/Symptoms: Rough idling, engine misfires, check engine light illuminated with codes related to camshaft position.
  • Solution: Replacement of the faulty camshaft adjuster solenoid.
  • Estimated Cost to Fix: $300 - $700+
  • Recalls: None Found

Transmission

9-Speed Automatic (9G-Tronic)

• Rough or Delayed Shifting
  • Description/Symptoms: Noticeable hesitation or jerky shifts between gears, especially when cold.
  • Solution: Software update/reprogramming of the transmission control module (TCM). In severe cases, valve body replacement may be required.
  • Estimated Cost to Fix: $200 - $500 (software update), $1500 - $3000+ (valve body replacement)
  • Recalls: None Found
• Transmission Oil Leaks
  • Description/Symptoms: Visible leaks near the transmission pan or around the transmission housing.
  • Solution: Replacement of the transmission pan gasket or sealing sleeves.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Suspension

• Air Suspension Compressor Failure (if equipped with optional air suspension)
  • Description/Symptoms: Vehicle sagging on one or more corners, failure of the air suspension system to level the vehicle, error messages displayed on the instrument cluster.
  • Solution: Replacement of the air suspension compressor.
  • Estimated Cost to Fix: $1200 - $2500+
  • Recalls: None Found
• Air Strut Leaks (if equipped with optional air suspension)
  • Description/Symptoms: Hissing sound from the air struts, vehicle sagging on one or more corners, uneven ride height.
  • Solution: Replacement of the leaking air strut.
  • Estimated Cost to Fix: $1500 - $3000+ per strut
  • Recalls: None Found

Electrical

• Battery Drain Issues
  • Description/Symptoms: Vehicle failing to start after sitting for a short period of time, frequent jump starts required.
  • Solution: Diagnosis to identify the parasitic drain. Could involve replacing the battery, faulty modules, or wiring harness issues.
  • Estimated Cost to Fix: $200 - $1000+ depending on the cause
  • Recalls: None Found
• Infotainment System Freezing/Crashing
  • Description/Symptoms: The COMAND infotainment system freezes, crashes, or becomes unresponsive.
  • Solution: Software update. If issue persists, the COMAND unit itself may need to be replaced.
  • Estimated Cost to Fix: $100-$300 (software update), $1500-$3000+ (COMAND unit replacement)
  • Recalls: None Found

Exterior

• Convertible Top Malfunctions
  • Description/Symptoms: The convertible top fails to open or close properly, makes unusual noises during operation, or gets stuck mid-cycle.
  • Solution: Diagnosis of the convertible top mechanism, hydraulic pump, or sensors. Repair or replacement of the faulty components.
  • Estimated Cost to Fix: $500 - $3000+ depending on the component
  • Recalls: None Found

Interior

• Seat Heater Failure
  • Description/Symptoms: Seat heaters fail to function, providing little to no heat.
  • Solution: Replacement of the seat heating element or control module.
  • Estimated Cost to Fix: $300 - $1000+ per seat
  • Recalls: None Found

Summary

The 2019 Mercedes-Benz SL450, while generally reliable, can exhibit issues in its engine, transmission, suspension, electrical system, convertible top and interior components. The most commonly reported issues involve oil leaks and rough transmission shifting. While some issues can be resolved with software updates, others require costly component replacements. Potential buyers should be aware of these potential problems and carefully inspect the vehicle before purchasing. The severity and cost of these issues range from minor inconveniences to major repairs, potentially impacting the overall ownership experience.