2005 Mercedes-Benz SL600

The 2005 Mercedes-Benz SL600 is a luxurious and powerful roadster, part of the R230 generation. It features a potent 5.5L Twin-Turbo V12 engine producing 493 horsepower and 590 lb-ft of torque, paired with a 5-speed automatic transmission. Other engine options for the SL in 2005 included various V6 and V8 engines. Owners often praise the SL600 for its exhilarating performance, refined interior, and advanced features like the Active Body Control (ABC) suspension. Downsides often cited are the high maintenance costs, complex electronics, and potential for expensive repairs, particularly with the V12 engine and ABC system.

Engine

5.5L Twin-Turbo V12 (M275)

• Oil Leaks
  • Description/Symptoms: Oil leaks from various engine seals and gaskets, particularly around the valve covers and rear main seal. Burning oil smell, visible oil drips.
  • Solution: Replace the leaking gaskets and seals.
  • Estimated Cost to Fix: $500 - $2500+
  • Recalls: None Found
• Ignition Coil Failure
  • Description/Symptoms: Misfires, rough running engine, check engine light illuminated. Diagnostic codes indicating misfires on specific cylinders. The M275 engine has two spark plugs per cylinder, increasing the likelihood of coil issues.
  • Solution: Replace the faulty ignition coil(s) and spark plugs.
  • Estimated Cost to Fix: $200 - $800+ (depending on how many coils need replacing)
  • Recalls: None Found
• Turbocharger Issues
  • Description/Symptoms: Loss of power, whistling or whining noises from the engine, check engine light.
  • Solution: Repair or replace the turbocharger(s).
  • Estimated Cost to Fix: $2500 - $6000+
  • Recalls: None Found
• Coolant Leaks
  • Description/Symptoms: Coolant leaks can occur from the radiator, hoses, water pump, and expansion tank. Overheating can result from these issues.
  • Solution: Replacing the faulty parts.
  • Estimated Cost to Fix: $200 - $1500+
  • Recalls: None Found

Transmission

5-Speed Automatic (722.6)

• Valve Body Issues
  • Description/Symptoms: Harsh or erratic shifting, slipping between gears, delayed engagement.
  • Solution: Replace or rebuild the valve body.
  • Estimated Cost to Fix: $800 - $2000+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration at low speeds, stalling, difficulty shifting.
  • Solution: Replace the torque converter.
  • Estimated Cost to Fix: $1200 - $3000+
  • Recalls: None Found

Suspension

• Active Body Control (ABC) System Leaks and Failures
  • Description/Symptoms: Vehicle sagging on one or more corners, ride height issues, stiff or bouncy ride, warning lights illuminated. Leaks from ABC struts, pump, or hoses.
  • Solution: Replace faulty ABC components (struts, pump, valve block, hoses). Flush and refill the ABC system with new fluid.
  • Estimated Cost to Fix: $1000 - $6000+ (can be significantly higher depending on the extent of the damage)
  • Recalls: None Found
• ABC Pump Failure
  • Description/Symptoms: The ABC pump is responsible for maintaining pressure to the ABC system. When the pump fails, the system is unable to function and ride height issues will arise.
  • Solution: Replace the pump.
  • Estimated Cost to Fix: $1000 - $2500+
  • Recalls: None Found

Electrical

• Sensor Failures
  • Description/Symptoms: Various warning lights illuminated (ABS, ESP, etc.), inaccurate readings from sensors (e.g., wheel speed sensors, oxygen sensors), performance issues.
  • Solution: Diagnose and replace the faulty sensor(s).
  • Estimated Cost to Fix: $200 - $800+ (per sensor)
  • Recalls: None Found
• Battery Drain Issues
  • Description/Symptoms: Battery drains quickly, requiring frequent jump starts. Can be caused by faulty modules or parasitic draws.
  • Solution: Diagnose and repair the source of the battery drain.
  • Estimated Cost to Fix: $150 - $1000+ (depending on the cause)
  • Recalls: None Found
• Convertible Top Malfunctions
  • Description/Symptoms: Top fails to open or close properly, gets stuck, or makes unusual noises. Can be caused by hydraulic leaks, sensor failures, or motor issues.
  • Solution: Diagnose and repair the convertible top system. This might include repairing the hydraulic cylinders or pump.
  • Estimated Cost to Fix: $500 - $3000+
  • Recalls: None Found

Exterior

• Hydraulic Cylinder Leaks (Convertible Top)
  • Description/Symptoms: Leaks in the hydraulic cylinders of the convertible hardtop system cause the top to operate slowly, unevenly, or not at all. Fluid leaks are often visible.
  • Solution: Rebuild or replace the leaking cylinders.
  • Estimated Cost to Fix: $500 - $2000+
  • Recalls: None Found

Interior

• Command System Issues
  • Description/Symptoms: The COMAND system can experience issues with the navigation, audio, and display functions.
  • Solution: Diagnose and repair or replace the COMAND unit or related components.
  • Estimated Cost to Fix: $300 - $2000+
  • Recalls: None Found

Summary The 2005 Mercedes-Benz SL600, while offering a luxurious and powerful driving experience, is prone to several common issues. The V12 engine can suffer from oil leaks and ignition coil failures, leading to expensive repairs. The ABC suspension is a known weak point, with potential leaks and failures that can be very costly to address. Electrical issues, including sensor failures and battery drain, can also arise. The convertible top mechanism, relying on hydraulics, can also present problems. Potential buyers should be aware of these common issues and factor in the high maintenance costs associated with this vehicle. The severity of the issues ranges from moderate to severe, and the associated costs can be significant.