2003 INFINITI Q45

2003 INFINITI Q45

Overview

The 2003 Infiniti Q45, a luxury sedan, aimed to blend performance with comfort. While generally considered a well-built vehicle for its era, like any car, it has specific areas where owners have reported issues. This analysis focuses on common technical reliability concerns beyond routine maintenance, providing insights into potential problem areas for prospective buyers or current owners. Understanding these potential issues can help in proactive maintenance and budgeting for repairs.

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Engine

4.5L V8 (VK45DE)

Timing Chain Tensioner Wear

• Symptoms: Rattling noise from the front of the engine, especially on startup; potential for increased emissions.
• Solution: Replacement of timing chain tensioners and guides.
• Cost: $1200 - $2500

Oil Leaks (Valve Covers/Gaskets)

• Symptoms: Visible oil on the engine block, burning oil smell, low oil level.
• Solution: Replacement of valve cover gaskets and/or other engine seals.
• Cost: $400 - $800

Transmission

5-Speed Automatic (RE5R05A)

Harsh Shifting / Delayed Engagement

• Symptoms: Jerky gear changes, hesitation when shifting into Drive or Reverse, potential for slipping.
• Solution: Transmission fluid and filter service, solenoid replacement, or full transmission rebuild.
• Cost: $500 - $3000+

Suspension

Standard Chassis

Front Suspension Bushing Wear

• Symptoms: Clunking or rattling noises over bumps, vague steering feel, uneven tire wear.
• Solution: Replacement of worn control arm bushings.
• Cost: $300 - $600

Electrical

Body Control Module (BCM)

Intermittent Electrical Gremlins

• Symptoms: Malfunctioning power windows, door locks, interior lights, or dashboard warning lights appearing randomly.
• Solution: Diagnosis and potential reprogramming or replacement of the BCM.
• Cost: $500 - $1200

Alternator

Premature Failure

• Symptoms: Dimming headlights, battery warning light, difficulty starting, dead battery.
• Solution: Replacement of the alternator.
• Cost: $400 - $700

Exterior

Paint & Body

Clear Coat Peeling

• Symptoms: Fading or peeling clear coat, especially on horizontal surfaces like the roof and hood.
• Solution: Professional repainting of affected areas.
• Cost: $500 - $2000+

Interior

Climate Control System

Blend Door Actuator Failure

• Symptoms: Inability to control temperature (stuck on hot or cold), air only coming from certain vents.
• Solution: Replacement of the blend door actuator(s).
• Cost: $200 - $500

Infotainment System

Navigation System Glitches

• Symptoms: Screen freezing, inaccurate GPS location, system unresponsiveness.
• Solution: Software update or replacement of the navigation unit.
• Cost: $300 - $1000

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Summary Verdict

The 2003 Infiniti Q45 is a capable luxury sedan, but potential buyers should be aware of common issues. The engine’s timing chain tensioners and oil seals are known weak points, and the transmission can develop shifting problems. Electrical gremlins related to the BCM and premature alternator failure are also reported. Suspension bushings and exterior paint issues are not uncommon with age. Interior climate control and navigation system glitches can detract from the luxury experience. While not overwhelmingly problematic, these areas represent the most frequent technical concerns for this model, requiring attention and potential repair costs.