2004 Mercedes-Benz S430

The 2004 Mercedes-Benz S430 is a luxury sedan known for its comfortable ride, elegant styling, and advanced features for its time. It was available with a 4.3L V8 engine producing 275 horsepower and 295 lb-ft of torque. Some owners appreciate the smooth ride and powerful engine, while others find the car expensive to maintain and prone to electrical issues. Other engine options included the S500 with a 5.0L V8 (302 hp, 339 lb-ft) and the S600 with a 5.5L V12 (493 hp, 590 lb-ft). All engine options were paired with a 5-speed automatic transmission.

Engine

4.3L V8

• Oil Leaks
  • Description/Symptoms: Oil leaks are common from various locations, including the valve cover gaskets, oil filter housing, and rear main seal. Symptoms include visible oil leaks, burning oil smell, and low oil levels.
  • Solution: Replace the leaking gaskets or seals.
  • Estimated Cost to Fix: $200 - $1000+ depending on the location and severity of the leak.
  • Recalls: None Found
• Crank Position Sensor Failure
  • Description/Symptoms: The crank position sensor can fail, causing the engine to stall, run poorly, or not start at all.
  • Solution: Replace the crank position sensor.
  • Estimated Cost to Fix: $150 - $300+
  • Recalls: None Found

5.0L V8

• Oil Leaks
  • Description/Symptoms: Similar to the 4.3L, oil leaks can occur from valve cover gaskets, oil filter housing, and rear main seal.
  • Solution: Replace the leaking gaskets or seals.
  • Estimated Cost to Fix: $200 - $1000+ depending on the location and severity of the leak.
  • Recalls: None Found
• Air Mass Sensor Failure
  • Description/Symptoms: Engine runs rough, loses power, or stalls. Check engine light is often illuminated.
  • Solution: Replace the air mass sensor.
  • Estimated Cost to Fix: $200 - $400+
  • Recalls: None Found

5.5L V12

• Ignition Coil Failure
  • Description/Symptoms: Misfires, rough running engine, and check engine light. The V12 has two ignition coils per cylinder bank.
  • Solution: Replace the faulty ignition coil(s).
  • Estimated Cost to Fix: $200 - $400+ per coil (labor intensive due to the V12 configuration).
  • Recalls: None Found
• Oil Leaks
  • Description/Symptoms: Leaks from valve covers, rear main seal, and other locations. The V12 engine is more complex, so leaks can be more difficult to diagnose and repair.
  • Solution: Replace the leaking gaskets/seals.
  • Estimated Cost to Fix: $500 - $1500+ due to the increased complexity of the V12.
  • Recalls: None Found

Transmission

5-Speed Automatic (All Engines)

• Transmission Conductor Plate Failure
  • Description/Symptoms: Harsh shifting, failure to shift, or getting stuck in a gear. Can also trigger “Limp Home” mode.
  • Solution: Replace the transmission conductor plate and filter.
  • Estimated Cost to Fix: $800 - $1500+
  • Recalls: None Found
• Valve Body Issues
  • Description/Symptoms: Erratic shifting, slipping, or delayed engagement.
  • Solution: Repair or replace the valve body.
  • Estimated Cost to Fix: $1000 - $2000+
  • Recalls: None Found

Suspension

• Airmatic Suspension Failure
  • Description/Symptoms: The Airmatic suspension is prone to failure, resulting in a sagging vehicle, rough ride, or suspension malfunction warning lights. Leaks can occur in the air struts, compressor, or valve block.
  • Solution: Replace faulty air struts, compressor, or valve block.
  • Estimated Cost to Fix: $800 - $2000+ per strut; $500 - $1000+ for the compressor; $300 - $500+ for the valve block.
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: The car’s battery drains quickly, especially if the car sits for a few days. This can be caused by a faulty control module, a malfunctioning component that doesn’t shut off properly, or a parasitic draw.
  • Solution: Diagnose and repair the source of the battery drain.
  • Estimated Cost to Fix: $100 - $500+ depending on the complexity of the issue.
  • Recalls: None Found
• Electronic Control Module (ECU) Issues
  • Description/Symptoms: Various engine, transmission, and other system malfunctions. Can be difficult to diagnose without specialized equipment.
  • Solution: Replace or reprogram the ECU.
  • Estimated Cost to Fix: $800 - $2000+
  • Recalls: None Found
• Instrument Cluster Pixelation
  • Description/Symptoms: Pixels on the instrument cluster display fade or disappear, making it difficult to read information.
  • Solution: Repair or replace the instrument cluster.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust can develop, particularly around the wheel arches, door bottoms, and other areas prone to moisture.
  • Solution: Repair or replace the affected panels.
  • Estimated Cost to Fix: $200 - $1000+ per panel depending on the severity.
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: The sunroof may fail to open or close properly, or it may leak.
  • Solution: Repair or replace the sunroof motor, tracks, or seals.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found
• Center Console Electronics Failure
  • Description/Symptoms: The COMAND system (navigation, audio, climate control) may malfunction, causing issues with the radio, navigation, and other features.
  • Solution: Repair or replace the COMAND unit.
  • Estimated Cost to Fix: $500 - $1500+
  • Recalls: None Found

Summary

The 2004 Mercedes-Benz S430, while a luxurious vehicle, is prone to several issues, particularly with its Airmatic suspension, electrical systems, and transmission. Engine oil leaks are also common across all engine options. The severity of these issues ranges from minor inconveniences to major repairs, and the cost to fix can be significant, especially with the Airmatic suspension and complex electrical problems. Potential buyers should be aware of these common issues and factor in maintenance costs when considering purchasing this vehicle.