The 2012 Infiniti M56 packs Nissan's VK56VD 5.6L V8 with known catastrophic engine failure issues from improper galley gasket installation at the factory, plus typical high-performance transmission cooling and driveline concerns. When the engine doesn't grenade, it's a solid luxury sport sedan, but that engine risk looms large.
Catastrophic Engine Failure - Gallery Gasket Defect
Occasional · high severityTypical onset: 60,000-120,000 mi
Symptoms: Sudden loss of oil pressure with no warning, Metallic knocking or complete engine seizure, Oil starvation damage to bearings, crank, and pistons, Often happens without prior symptoms or low oil level
Fix: Factory-installed oil gallery gaskets can fail or were improperly seated, starving the engine of oil. Requires complete engine rebuild or replacement. 25-35 labor hours for rebuild, 18-22 hours for used engine swap. Includes all bearings, pistons, rings, gaskets, machine work, and fluids.
Estimated cost: $8,000-15,000
Transmission Oil Cooler Failure
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Transmission fluid in coolant or coolant in transmission (strawberry milkshake fluid), Transmission slipping or harsh shifting after cooler breach, Overheating transmission, especially under load, Coolant loss with no external leaks
Fix: Internal cooler in radiator fails, cross-contaminating fluids and destroying transmission. Requires radiator replacement, complete transmission flush (sometimes replacement if contaminated too long), new fluid and filter. 6-9 hours labor if caught early; add 15-20 hours if transmission rebuild needed.
Estimated cost: $1,800-3,500
Rear Driveshaft Center Support Bearing Failure
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Clunk or vibration from under vehicle during acceleration, Rumbling or humming noise at highway speeds, Vibration that changes with load or coast, Visible play or grease leaking from center carrier bearing
Fix: Two-piece driveshaft uses center support bearing that wears out from heat and stress. Requires driveshaft removal and carrier bearing replacement. Some shops replace entire driveshaft assembly for reliability. 2.5-3.5 hours labor.
Estimated cost: $600-1,200
Transmission Mount Collapse
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Clunk when shifting from Park to Drive or Reverse, Excessive drivetrain movement felt through chassis, Vibration at idle in gear, Visible sagging or cracking of rubber mount
Fix: Heavy V8 and 7-speed transmission stress the rear transmission mount. Hydraulic mount deteriorates, allowing excessive movement. Replacement requires supporting transmission and drivetrain. 2-3 hours labor for rear mount, sometimes front mount needed too.
Estimated cost: $400-800
Fuel System Contamination - In-Tank Filter Clogging
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Intermittent stalling or hesitation under acceleration, Rough idle or stumbling when fuel tank below half, Check engine light with fuel trim or fuel pressure codes, Hard starting after sitting
Fix: Internal fuel filter sock in tank clogs from debris or aged fuel. Requires fuel pump module removal, tank drop or access through rear seat/trunk area. Replace fuel pump assembly with filter and sock. 3-4 hours labor.
Estimated cost: $800-1,400
Timing Chain Tensioner and Guide Wear
Occasional · high severityTypical onset: 100,000-150,000 mi
Symptoms: Rattling from front of engine on cold start, Metallic ticking that disappears after warmup, Check engine light with cam/crank correlation codes, Rough running or misfires if chain has jumped
Fix: VK56 uses primary and secondary timing chains with plastic guides that wear. If caught early, replace tensioners, guides, and chains. Requires front engine disassembly, water pump replacement while in there. 12-16 hours labor. Ignore it and risk valve damage.
Estimated cost: $2,800-4,500
Buy only with comprehensive pre-purchase inspection and proof of meticulous maintenance; the engine time-bomb risk makes sub-$12k examples a gamble, but clean low-mileage survivors under 60k are worth considering if you love the performance.
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.