The 2004 FX45 pairs Infiniti luxury with a powerful 4.5L V8 and AWD capability, but suffers from catastrophic engine failure due to cylinder liner wear and transmission cooler leaks that can destroy the 5-speed automatic if not caught early.
Cylinder Liner / Piston Ring Failure (VK45DE Engine)
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Excessive oil consumption (1+ quart per 1,000 miles), Blue smoke on cold start or acceleration, Loss of compression and power, Check engine light with misfire codes (P030X series)
Fix: Requires full engine rebuild or replacement. Cylinder liners wear prematurely causing blow-by and oil burning. Some shops sleeve the block, others source low-mileage used engines. Rebuild takes 18-24 labor hours, swap takes 12-16 hours depending on accessories.
Estimated cost: $5,500-9,500
Transmission Oil Cooler Line Corrosion and Leaks
Common · high severityTypical onset: 70,000-110,000 mi
Symptoms: ATF pooling under vehicle near radiator area, Transmission slipping or harsh shifts after leak develops, Milky transmission fluid if cooler fails internally (fluid cross-contamination), Overheating transmission warnings on dash
Fix: Steel cooler lines rust through where they run along frame rails. If internal cooler fails, coolant mixes with ATF and destroys transmission internals. External leak requires line replacement (3-4 hours). Internal failure requires radiator replacement plus transmission rebuild (20-25 hours total).
Estimated cost: $400-800 (lines only), $4,500-7,000 (with transmission rebuild)
Front Lower Control Arm Bushing Failure
Common · medium severityTypical onset: 60,000-90,000 mi
Symptoms: Clunking noise over bumps from front suspension, Steering wander or imprecise handling, Uneven tire wear on inside edges, Vibration through steering wheel at highway speeds
Fix: Rubber bushings separate and tear, especially in salt-belt states. Control arms are not serviceable separately—must replace entire arms. Both sides typically done together. 3-4 hours labor plus alignment.
Estimated cost: $800-1,200
Transfer Case Oil Pump Seal Leak (AWD Models)
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Gear oil dripping from rear of transmission/front of transfer case, Whining noise from transfer case when accelerating, AWD warning light if fluid level drops significantly, Burning oil smell after highway driving
Fix: Internal seal on transfer case pump wears out. Requires dropping exhaust and driveshaft, removing transfer case for seal replacement. 5-7 hours labor. Neglecting this can starve the transfer case and cause internal damage.
Estimated cost: $900-1,400
Rear Differential Bushing and Mount Wear
Occasional · low severityTypical onset: 80,000-120,000 mi
Symptoms: Clunking when shifting from drive to reverse, Driveline vibration between 40-60 mph, Banging noise under hard acceleration, Visible sagging of differential on inspection
Fix: Rubber mounts and bushings supporting rear differential deteriorate. Requires dropping differential slightly to access mounts. 2-3 hours labor. Often replaced with polyurethane upgrades.
Estimated cost: $400-700
Sunroof Drain Tube Clogs and Water Leaks
Occasional · low severitySymptoms: Water pooling in front footwells after rain or car wash, Headliner sagging or staining near A-pillars, Musty smell in cabin, Water sloshing sound behind dashboard
Fix: Drain tubes clog with debris and back up, overflowing into cabin. Requires removing A-pillar trim and clearing tubes with compressed air or wire. Sometimes tubes separate at joints and need reattachment. 1-2 hours labor.
Estimated cost: $150-350
Only buy if you can verify engine compression test results and transmission service history—the VK45DE liner issue is a ticking time bomb that can total an otherwise solid luxury SUV.
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.