The 2015 DB9's 6.0L V12 is a high-strung naturally aspirated engine that delivers thrilling performance but demands meticulous maintenance. When neglected or driven hard without proper warm-up/cool-down, these engines can suffer catastrophic bearing and piston failures that cost more than many used cars.
Connecting Rod and Main Bearing Failure
Occasional · high severityTypical onset: 40,000-80,000 mi
Symptoms: Metallic knocking from lower engine, especially on cold start, Oil pressure warning light, Metal shavings in oil during changes, Sudden loss of power
Fix: Complete engine teardown required. Most shops recommend short block replacement or full rebuild with all bearings, rod bolts, and machining. Expect 40-60 hours labor depending on whether you pull the engine or work in-chassis. This is the DB9's Achilles heel—inadequate oil flow during cold starts and aggressive driving before proper warm-up kills bearings prematurely.
Estimated cost: $18,000-35,000
Piston Ring Land Failure and Scoring
Occasional · high severityTypical onset: 50,000-90,000 mi
Symptoms: Excessive blue smoke on startup, High oil consumption (1 qt per 500-800 miles), Misfires and rough idle, Loss of compression in one or more cylinders
Fix: Requires cylinder head removal and piston replacement. Often discovered during compression testing after oil consumption complaints. Ring lands crack from detonation or heat cycles. Budget 35-50 hours for pistons-all replacement including honing, new rings, gaskets, and timing chain service while you're in there.
Estimated cost: $12,000-22,000
Transmission Control Module and Shifting Issues
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Harsh shifting or delayed engagement, Stuck in gear or limp mode, Transmission fault warnings on dash, Clunking into reverse
Fix: The Touchtronic II transmission is robust but the TCM can fail or require reprogramming. Sometimes it's just software updates (2 hours), but failed modules need replacement and adaptation. Also check transmission mounts—they collapse and cause harsh shifting that mimics TCM problems. Mount replacement is 3-4 hours.
Estimated cost: $800-3,500
Fuel Filter Clogging and Fuel System Contamination
Common · medium severitySymptoms: Hesitation under acceleration, Stumbling at idle, Hard starting when hot, Check engine light with lean codes
Fix: The in-tank fuel filter gets neglected because it's not in the regular service schedule. Recommend replacement every 30,000 miles or if car has sat for extended periods. Requires dropping the fuel tank. Budget 4-5 hours. Contaminated fuel from storage is common with these low-mileage garage queens.
Estimated cost: $600-1,200
Door Latch and Lock Mechanism Failure
Common · low severitySymptoms: Door won't open from inside or outside, Door ajar warning stays on, Central locking intermittent, Manual release cable required to exit
Fix: The door latch assemblies fail mechanically—plastic gears strip or cables seize. This was recalled but many cars weren't fixed. Replacement latch assemblies with improved parts are available. Figure 3-4 hours per door including door panel removal and calibration.
Estimated cost: $800-1,500
Transmission Oil Cooler Line Leaks
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Transmission fluid puddles under car, Burnt smell from transmission area, Low fluid level warnings, Shifting becomes erratic
Fix: The cooler lines run along the undercarriage and develop leaks at crimp points or get damaged by road debris. Requires lift access and sometimes subframe dropping for proper replacement. 4-6 hours depending on which line fails. Don't ignore—running low on ATF will grenade the transmission.
Estimated cost: $1,200-2,200
Only buy if you have a $10k cushion for inevitable engine work and accept that this is a high-stakes ownership experience—magical when running, financial catastrophe when not.
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.