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2004 INFINITI Q45

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By Research the Car 5 min read

The 2004 INFINITI Q45 is a full-size luxury sedan known for its powerful engine, comfortable ride, and elegant styling. It features a 4.5-liter V8 engine producing 340 horsepower and 333 lb-ft of torque. The only transmission option available for this model year was a 5-speed automatic. Owners generally appreciate the Q45’s smooth acceleration, spacious interior, and refined driving experience. Some common complaints revolve around its relatively poor fuel economy, complex electronic systems, and higher maintenance costs compared to some competitors.

Engine

4.5L VK45DE V8

  • Oil Consumption
    • Description/Symptoms: Some owners have reported excessive oil consumption, requiring frequent top-offs between oil changes. This can be due to worn piston rings or valve stem seals. Symptoms include blue smoke from the exhaust, a burning oil smell, and consistently low oil levels.
    • Solution: A compression test can help diagnose the issue. If rings or seals are the problem, an engine rebuild or replacement may be necessary.
    • Estimated Cost to Fix: $2,500 - $6,000+ (Engine Rebuild/Replacement)
    • Recalls: None Found
  • Timing Chain Tensioner Failure
    • Description/Symptoms: The timing chain tensioner can fail, leading to rattling noises from the engine, especially upon startup. If left unaddressed, this can cause timing chain slippage and potential engine damage.
    • Solution: Replacement of the timing chain tensioner, and possibly the timing chain itself if damage has occurred.
    • Estimated Cost to Fix: $800 - $1500
    • Recalls: None Found
  • Catalytic Converter Failure
    • Description/Symptoms: Catalytic converters may fail due to age, overheating, or contamination. Symptoms include a check engine light (often with codes P0420 or P0430), reduced engine performance, and a sulfur-like smell from the exhaust.
    • Solution: Replacement of the faulty catalytic converter(s).
    • Estimated Cost to Fix: $800 - $2000 per converter
    • Recalls: None Found

Transmission

5-Speed Automatic

  • Transmission Slippage
    • Description/Symptoms: Transmission slippage, especially between gears, and harsh shifting are common complaints. This can be caused by worn clutch packs, a failing valve body, or low transmission fluid.
    • Solution: A transmission fluid flush may resolve minor issues. For more severe problems, a valve body replacement or a complete transmission rebuild or replacement might be necessary.
    • Estimated Cost to Fix: $200 (Fluid Flush) - $3,000+ (Rebuild/Replacement)
    • Recalls: None Found
  • Torque Converter Failure
    • Description/Symptoms: Shuddering or vibration at low speeds, particularly when the torque converter is locking up. Can also cause stalling.
    • Solution: Torque converter replacement.
    • Estimated Cost to Fix: $800 - $1500
    • Recalls: None Found

Suspension

  • Air Suspension Issues
    • Description/Symptoms: The air suspension system is prone to problems, including compressor failure, air leaks from struts or lines, and height sensor malfunctions. Symptoms include the car sitting unevenly, the suspension not adjusting properly, and a suspension warning light.
    • Solution: Replacement of the faulty compressor, struts, air lines, or height sensors. Some owners convert to a traditional coil-over suspension system to avoid recurring air suspension issues.
    • Estimated Cost to Fix: $500 - $1500 per strut or compressor, $1000-3000+ for coilover conversion.
    • Recalls: None Found
  • Control Arm Bushing Wear
    • Description/Symptoms: Worn control arm bushings can cause clunking noises from the suspension, especially when going over bumps. It can also lead to loose steering and uneven tire wear.
    • Solution: Replacement of the worn control arm bushings or the entire control arm assembly.
    • Estimated Cost to Fix: $300 - $800 per control arm.
    • Recalls: None Found

Electrical

  • Navigation System Failure
    • Description/Symptoms: The factory navigation system is known to fail or become outdated.
    • Solution: Replacement or repair of the navigation unit, or installation of an aftermarket system.
    • Estimated Cost to Fix: $200 - $800+ (Repair), $300+ (Aftermarket Replacement)
    • Recalls: None Found
  • Battery Drain
    • Description/Symptoms: Excessive battery drain can occur due to faulty electrical components or parasitic draw.
    • Solution: Thoroughly diagnose the electrical system to identify the source of the drain. Possible causes include a failing alternator, a short circuit, or a malfunctioning module.
    • Estimated Cost to Fix: Varies greatly depending on the source of the drain; $100 - $500+
    • Recalls: None Found
  • BCM (Body Control Module) Issues
    • Description/Symptoms: Malfunctions in the BCM can cause a variety of electrical problems, including issues with the power windows, door locks, lighting, and security system.
    • Solution: BCM replacement or reprogramming.
    • Estimated Cost to Fix: $500 - $1200
    • Recalls: None Found

Exterior

  • Headlight Condensation
    • Description/Symptoms: Moisture buildup inside the headlight housings.
    • Solution: Remove the headlights, dry them, and reseal them, or replace the headlight assemblies.
    • Estimated Cost to Fix: $100 - $300 (Reseal), $300 - $800+ (Replacement)
    • Recalls: None Found

Interior

  • Sunroof Issues
    • Description/Symptoms: Sunroof may fail to open or close properly, or may leak.
    • Solution: Repair or replacement of the sunroof motor, track, or seals.
    • Estimated Cost to Fix: $200 - $800
    • Recalls: None Found
  • Climate Control Malfunctions
    • Description/Symptoms: The climate control system can experience issues with the blower motor, blend doors, or temperature sensors, leading to inconsistent or incorrect temperatures.
    • Solution: Replacement of the faulty component(s).
    • Estimated Cost to Fix: $200 - $800
    • Recalls: None Found

Summary

The 2004 INFINITI Q45, while a luxurious and powerful sedan, is prone to several issues related to its engine, transmission, suspension, and electrical systems. Engine issues such as oil consumption and timing chain tensioner failure can be costly to repair. The air suspension system is a common source of problems. Electrical issues with the navigation system, battery drain, and BCM can also occur. The severity and cost of these issues can vary greatly, but potential buyers should be aware of these common problems before purchasing a used 2004 Q45. These issues make pre-purchase inspections all the more important.

INFINITI, Q45
INFINITI Q45 2004
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