2016 INFINITI QX80

Typical onset: 60,000-120,000 mi

Symptoms: Cold-start rattle for 2-3 seconds that progressively worsens, Check engine light with cam/crank correlation codes (P0021, P0011), Sudden loss of power, metal shavings in oil, complete engine seizure if guides disintegrate

Fix: The plastic secondary chain guides (upper) wear and break apart, letting slack chains jump timing or fragments circulate through the engine destroying bearings, cylinder walls, and heads. Preventive fix is front timing cover removal, guide and chain replacement—12-16 hours labor. If it grenades the engine, you're looking at short block or complete rebuild with pistons, rings, bearings, and often head work. 40-60 hours labor for full rebuild.

Estimated cost: $3,500-6,000 preventive (chains/guides); $12,000-18,000 full rebuild after failure

Typical onset: 70,000-130,000 mi

Symptoms: Red ATF dripping near radiator or under front of vehicle, Transmission slipping or delayed shifts if fluid level drops significantly, Visible corrosion or green crusty buildup on steel cooler lines at crimp points

Fix: Steel cooler lines rust through where they crimp to rubber hoses, especially in salt states. Aftermarket stainless lines are available and recommended. Requires lifting vehicle, dropping crossmember in some cases for access. 3-5 hours labor including fluid refill and system purge.

Estimated cost: $600-1,200

Typical onset: 80,000-120,000 mi

Symptoms: Clunk or thud on hard acceleration or when shifting from Park to Drive, Vibration at idle that changes when shifting into gear, Visible cracking or oil saturation of rubber mount

Fix: The rear transmission mount softens and tears, allowing excessive drivetrain movement. Replacement is straightforward—support trans with jack, unbolt mount, swap. 1.5-2.5 hours labor. OEM mount is hydraulic-damped; aftermarket options exist but may increase NVH.

Estimated cost: $350-650

Typical onset: 90,000-140,000 mi

Symptoms: Intermittent stalling, especially when fuel level is below half-tank, Erratic fuel gauge readings or stuck at empty/full, No-start with crank but no fuel pressure (pump motor failure)

Fix: In-tank fuel pump module fails—either the pump motor itself or the level sender. Requires dropping the tank or removing rear seat and access panel (QX80 has panel under third-row seat area). 3-4 hours labor. Always replace strainer and check fuel filter in-line if applicable.

Estimated cost: $800-1,400

Typical onset: 100,000-150,000 mi

Symptoms: Coolant smell or visible drips under front of vehicle, Slow coolant loss requiring top-ups between services, White residue or staining on radiator end tanks or hose connections

Fix: Plastic radiator end tanks crack at mounting tabs or hose necks; upper/lower hoses develop pinhole leaks at bends. Radiator replacement is 4-5 hours labor (requires condenser/front bumper support removal for access). Hoses alone are 1-2 hours.

Estimated cost: $600-1,000 hoses; $1,200-1,800 radiator

Typical onset: 80,000-130,000 mi

Symptoms: Harsh or delayed 2-3 or 3-4 shifts, Check engine light with transmission solenoid codes (P0745, P0750), Limp mode with transmission locked in 3rd or 4th gear

Fix: The RE7R01A transmission develops valve body wear and solenoid failures, often due to poor fluid maintenance. Fix requires pan drop, valve body removal, solenoid replacement, and sometimes full valve body replacement or reconditioning. 6-10 hours labor. Always replace pan gasket, filter, and do full fluid exchange.

Estimated cost: $1,800-3,500