2003 INFINITI FX45

4.5L V8FWDAUTOMATICgas
5-Year Cost of Ownership
$14,400 maintenance + known platform issues
~$2,880/yr · 240¢/mile equivalent · $5,159 maintenance + $8,541 expected platform issues
Common Problems & Known Issues

The 2003 FX45 pairs Nissan's VK45DE V8 with a RE5R05A five-speed automatic in a heavy luxury crossover. The platform is robust, but the engine has a catastrophic weakness: improper break-in or oil-change neglect leads to cylinder scoring and premature engine failure, often before 100,000 miles.

VK45DE Cylinder Scoring and Engine Failure

Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: Excessive oil consumption (1qt per 500-1000 mi), Blue smoke on cold start, Loss of compression, Check engine light with misfire codes, Eventually catastrophic failure with metal shavings in oil
Fix: No halfway fix exists; scored cylinders require complete short-block replacement or reman engine swap. 18-24 labor hours depending on shop familiarity with VQ/VK platform. Many owners find totaled vehicles due to repair cost exceeding value.
Estimated cost: $6,500-12,000

RE5R05A Transmission Oil Cooler Failure and Coolant Cross-Contamination

Common · high severity
Typical onset: 80,000-140,000 mi
Symptoms: Transmission fluid appears milky or 'strawberry milkshake' colored, Delayed or erratic shifting, Coolant loss with no external leaks, Transmission overheating or slipping, Radiator has ATF floating on top of coolant
Fix: Internal radiator-mounted cooler corrodes through, mixing coolant and ATF. Requires radiator replacement, external trans cooler install, complete trans flush (often 3-4x to clear contamination), and filter/fluid service. If contamination ran for weeks, transmission rebuild needed. 6-8 hours for preventive fix, 14-20 if trans needs teardown.
Estimated cost: $1,200-2,200 (preventive); $3,500-5,500 (with trans rebuild)

Transmission Mounts Collapsing

Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Heavy clunk on 1-2 or 2-3 upshift under throttle, Vibration at idle in Drive, Transmission 'thumps' when engaging Park or Reverse, Visible sagging of trans tail housing on lift
Fix: Hydraulic mounts fatigue from curb weight and V8 torque. Rear trans mount most common, but inspect all three. Replace in pairs minimum. 2.5-3.5 hours with proper lift access.
Estimated cost: $450-750

Front Lower Control Arm Bushings and Ball Joints

Occasional · medium severity
Typical onset: 90,000-130,000 mi
Symptoms: Clunking over bumps at low speed, Steering wander or vague on-center feel, Uneven inner tire wear, Play detectable with pry bar during inspection
Fix: Bushings deteriorate from weight and AWD torque vectoring stress. Infiniti sells complete assemblies only (no press-in bushings separately). Alignment mandatory after. 3-4 hours both sides with alignment.
Estimated cost: $900-1,400

Headlight Lens Crazing and Moisture Intrusion

Occasional · low severity
Symptoms: Cloudy, yellowed lens appearance, Moisture or condensation inside housing, Reduced night visibility, Bulb life shortened due to heat retention
Fix: UV degradation and seal failure on HID projector housings. Polishing helps short-term, but housings eventually need replacement. OEM discontinued; aftermarket quality inconsistent. 1.5 hours per side for housing R&R.
Estimated cost: $600-1,200 (pair, aftermarket)

Fuel Filter Clogging and Pump Pre-Failure

Occasional · medium severity
Typical onset: 100,000+ mi
Symptoms: Hesitation under moderate-to-heavy throttle, Stumble or surge at highway speeds, Check engine light with lean codes, Hard starting after sitting overnight
Fix: In-tank fuel pump strainer and inline filter both clog if fuel quality poor. Pump module replacement often needed by 120k. Tank drop required. 3-4 hours labor.
Estimated cost: $700-1,100
Owner tips
  • Change engine oil every 3,500-4,000 miles with quality 5W-30 synthetic; the VK45DE is unforgiving of extended intervals.
  • Install external transmission cooler immediately and replace radiator proactively at 80k miles to prevent coolant cross-contamination.
  • Inspect transmission fluid color every oil change; any pink-red turning brown or milky means immediate action required.
  • Budget $1,500-2,500 annually for deferred maintenance catch-up on any high-mileage example.
Avoid unless you find one with bulletproof engine-rebuild and external-trans-cooler documentation; the VK45DE scoring issue makes most examples ticking time bombs by 80k miles.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
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