2009 INFINITI FX50

Typical onset: 60,000-120,000 mi

Symptoms: Low oil pressure warning at idle or startup, Ticking or knocking from lower engine, especially when warm, Metal shavings in oil or on magnetic drain plug, Sudden catastrophic failure with rod knock or seized bearing

Fix: The oil gallery gaskets—thin paper gaskets between the block halves—deteriorate and allow oil starvation to bearings. Once symptoms appear, damage is usually done. Requires full engine-out teardown: remove engine (12-15 hrs), split block, replace all bearings, gaskets, inspect crank/rods for scoring. Most shops quote replacement with used/reman engine instead because machine work often exceeds replacement cost. Reman installation runs 18-24 labor hours.

Estimated cost: $8,000-15,000

Typical onset: 70,000-130,000 mi

Symptoms: Pink or milky transmission fluid (coolant mixing), Transmission slipping or delayed engagement after cooler line leak, Coolant loss with no external leak visible, Harsh shifts or limp mode after contamination

Fix: The radiator-mounted transmission cooler develops internal leaks, allowing coolant into ATF. Once mixed, the transmission is often damaged internally. Proper fix: replace radiator (4-5 hrs), flush all cooling and transmission systems, replace transmission if contamination caused clutch pack damage (another 10-12 hrs for R&R). Many owners catch it early and survive with flush; others need full trans rebuild.

Estimated cost: $1,200-6,500

Typical onset: 80,000-140,000 mi

Symptoms: Clunking when shifting from Park to Drive or Reverse, Vibration at idle in gear, smooths out in Park/Neutral, Visible engine/transmission sag or misalignment on lift

Fix: The rubber transmission mounts fail from heat and age, especially on the V8 with its weight and torque. Replacement requires supporting the drivetrain, unbolting old mounts, installing new OEM or aftermarket units. Usually both trans mounts plus the rear engine mount need attention simultaneously. 3-4 labor hours total.

Estimated cost: $600-1,000

Typical onset: 90,000-150,000 mi

Symptoms: Rough idle, hesitation, or misfires under load, Check engine light with fuel trim or misfire codes, Hard starting or extended cranking when hot, Loss of power on acceleration

Fix: Direct-injection engines accumulate carbon, and old fuel clogs in-tank filters and high-pressure pump screens. Requires dropping fuel tank (2-3 hrs) to access pump assembly, replace filter/strainer, inspect pump. Sometimes high-pressure pump itself fails and needs replacement. Carbon cleaning via walnut-blasting intake valves adds another 4-5 hrs if intake deposits cause issues.

Estimated cost: $800-2,200

Typical onset: 100,000-160,000 mi

Symptoms: Harsh or delayed shifts, especially 2-3 or 3-4, Transmission slipping between gears under moderate throttle, Check engine light with transmission solenoid codes, Limp mode or refusal to shift past 3rd gear

Fix: The RE7R01A seven-speed auto develops valve body wear and solenoid failures over time. Requires transmission pan drop, valve body removal (6-8 hrs), solenoid pack replacement, and often valve body replacement or rebuild. If caught early, sometimes just solenoid pack replacement suffices. Fluid and filter replacement mandatory during repair.

Estimated cost: $1,800-3,500

Typical onset: 120,000-180,000 mi

Symptoms: Rattling noise from front of engine on cold start, subsides after 5-10 seconds, Check engine light with cam/crank correlation codes, Rough idle or misfires if timing has drifted, Metallic debris in oil if guides have disintegrated

Fix: VK50 uses plastic timing chain guides that wear and tensioners that lose pressure. If guides break, chain slaps block and valves contact pistons. Preventive replacement: engine-out recommended for thorough access (12-15 hrs total), replace all guides, tensioners, chains, and water pump while in there. Some techs do it in-chassis but access is brutal.

Estimated cost: $3,500-6,000