The 1997 DB7 is essentially a re-bodied Jaguar XJS platform with a supercharged AJ6 engine, sharing many of Jaguar's electrical gremlins and cooling challenges. Beautiful GT car, but parts availability and specialist labor make ownership expensive.
Nikasil Cylinder Liner Failure
Common · high severityTypical onset: 60,000-90,000 mi
Symptoms: Loss of compression in one or more cylinders, Excessive oil consumption, Rough idle and misfires, White smoke on cold start
Fix: Early AJ6 supercharged engines used Nikasil bore linings that are sulfur-sensitive. High-sulfur fuel causes corrosion and scoring. Fix requires complete engine rebuild with steel liner replacement or short block swap. 40-60 hours labor, often combined with gasket refresh.
Estimated cost: $12,000-18,000
Supercharger Bearing and Coupler Failure
Common · high severityTypical onset: 70,000-100,000 mi
Symptoms: Grinding or whining noise from supercharger, Loss of boost pressure, Metal shavings in intercooler, Check engine light with fuel trim codes
Fix: Eaton M90 supercharger bearings wear out, and the rubber coupler deteriorates. Requires supercharger removal, rebuild or replacement. If metal contamination occurs, intercooler must be cleaned or replaced. 12-16 hours labor.
Estimated cost: $3,500-5,500
Transmission Oil Cooler and Gearbox Issues
Common · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Harsh or delayed shifts, Transmission slipping in certain gears, Overheating transmission fluid, Leaks from cooler lines
Fix: The ZF 4HP automatic transmission runs hot, and the external oil cooler and lines frequently leak or clog. Transmission mounts also deteriorate causing harsh engagement. Cooler replacement 3-4 hours; full transmission service or rebuild 18-25 hours if internal damage occurs.
Estimated cost: $800-1,200 (cooler only); $4,500-7,500 (rebuild)
Electrical Gremlins and ECU Failures
Common · medium severitySymptoms: Intermittent no-start conditions, Random warning lights, Gauge cluster failures, Window and mirror controls inoperative, Instrument pack displaying incorrect data
Fix: Inherited Jaguar Lucas electrical architecture means corroded connectors, failing relays, and moisture-damaged ECUs are routine. Ground points under carpets corrode. Diagnosis is time-intensive; ECU repairs/replacements often needed. 4-12 hours diagnostic and repair depending on issue.
Estimated cost: $500-3,000
Cooling System Failures
Occasional · high severityTypical onset: 50,000-90,000 mi
Symptoms: Overheating under load, Coolant loss without visible leaks, Steam from engine bay, Heater blowing cold air
Fix: Plastic radiator end tanks crack, water pumps fail, and head gaskets leak (often related to Nikasil overheating events). Supercharged engine generates significant heat. Preventive replacement of entire cooling system recommended. Water pump 4-6 hours; head gaskets 20-30 hours if combined with liner inspection.
Estimated cost: $1,200-2,500 (radiator/pump); $6,000-10,000 (head gaskets)
Fuel System and Filter Clogging
Occasional · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Hesitation or stumbling under acceleration, Loss of boost control, Hard starting after sitting, Fuel smell from tank area
Fix: In-tank fuel pump pre-filters and inline filters clog from debris in aging tanks. Fuel pressure regulator diaphragms also fail. Pump access requires rear interior removal. 3-5 hours for filter and pump service.
Estimated cost: $800-1,500
Suspension Bushing and Shock Degradation
Common · low severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking over bumps, Wandering steering feel, Uneven tire wear, Rear axle tramp under hard acceleration
Fix: Rubber bushings in control arms, subframe mounts, and diff mounts perish. Bilstein shocks leak. Full suspension refresh recommended as preventive measure. Front arms and bushings 8-10 hours; rear 6-8 hours; shocks 4-6 hours.
Estimated cost: $2,500-4,500 (full refresh)
Only buy if you have a specialist mechanic nearby, a healthy repair fund, and accept that engine rebuilds are a when-not-if proposition — glorious to drive, punishing to own casually.
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.