The 1992 Q45 was Infiniti's flagship with a jewel-like 4.5L V8, but it's plagued by catastrophic engine failures from timing belt neglect and active suspension nightmares that can strand you. When maintained religiously, it's a luxury barge with German aspirations at Japanese prices—but maintenance history is everything.
Timing Belt Failure Leading to Complete Engine Destruction
Common · high severityTypical onset: 60,000-100,000 mi
Symptoms: Sudden loss of power and catastrophic noise, Engine won't start after belt snap, Bent valves, damaged pistons, scarred cylinder walls
Fix: This is an interference engine—when the belt goes, valves meet pistons at high speed. We've seen owners ignore the 60k service interval and pay the ultimate price. Full rebuild required: heads machined or replaced, all pistons, rings, bearings, head gaskets. Budget 40-60 hours labor for a proper rebuild. Prevention is a $800 timing belt job every 60k miles; neglect costs you the engine.
Estimated cost: $6,000-12,000
Active Suspension System Failure (Hydraulic Struts)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: One corner sits low, especially after sitting overnight, Suspension warning light on dash, Compressor runs constantly or not at all, Harsh ride or wallowing handling
Fix: The Full Active Suspension uses hydraulic struts with accumulators, and they leak. One strut is 4-5 hours to replace, but rarely do you replace just one. Compressor failures add another $1,200-1,500. Many owners convert to conventional coilovers (12-15 hours labor) rather than chase $1,800/corner OEM struts that are often NLA. Aftermarket conversions run $2,500-3,500 installed.
Estimated cost: $2,500-7,000
Transmission Oil Cooler Line and Mount Failures
Common · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Transmission fluid leaking from front of vehicle, Harsh shifting when cold, Transmission slipping or delayed engagement, Visible fluid on ground after parking
Fix: The steel cooler lines corrode where they connect to the radiator, and the rubber transmission mounts collapse, causing harsh engagement and driveline clunk. Cooler lines are 2-3 hours; we typically do both while we're in there. Mounts are another 2 hours. If the leak went unnoticed and the trans ran low, expect internal damage requiring rebuild (18-24 hours).
Estimated cost: $600-1,200
Fuel Filter Clogging and Fuel Pump Strain
Occasional · medium severityTypical onset: 100,000+ mi
Symptoms: Intermittent stalling at idle, Hesitation or stumble under acceleration, Hard starting when hot, Check engine light with lean codes
Fix: The in-tank fuel pump works harder when the filter clogs, and Nissan specified 30k mile filter changes that nobody does. By 100k, we see pumps failing alongside clogged filters. Filter is 1 hour, pump is 3-4 hours (drop tank). If you're doing the pump, replace the filter, sock screen, and pressure regulator while you're in there.
Estimated cost: $400-900
Alternator and Charging System Failures
Occasional · medium severityTypical onset: 120,000+ mi
Symptoms: Battery warning light flickering, Dimming headlights at idle, Dead battery after short trips, Electrical gremlins, radio resets
Fix: The 110-amp alternator struggles with all the active suspension and luxury electronics. Brushes wear, voltage regulators fail. We've seen charging voltage drop to 12.5V at idle. Replacement is straightforward, 1.5-2 hours, but quality remans are critical—cheap ones fail within a year. OEM Hitachi units are worth the premium.
Estimated cost: $500-800
Lower Ball Joints and Control Arm Bushings
Occasional · medium severityTypical onset: 90,000-130,000 mi
Symptoms: Clunking over bumps, Wandering steering, requires constant correction, Uneven tire wear on inside edges, Steering wheel off-center after alignment
Fix: The front lower control arms use pressed-in ball joints and large rubber bushings that deteriorate. You can't press new joints in reliably—most shops replace the entire arm (2 hours per side, 4 hours for both fronts). Alignment is mandatory afterward. If you're in there, inspect the upper arms too; their bushings go around the same time.
Estimated cost: $800-1,400
Buy only with impeccable maintenance records showing timing belt changes and recent suspension work, or budget $5k-8k immediately for deferred maintenance—these are money pits without history, but sublime highway cruisers when sorted.
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.