The 2002 XK8 with the 4.0L AJ-V8 is a beautiful grand tourer undermined by catastrophic engine failure from Nikasil cylinder liner issues and fragile plastic cooling components. Early AJ26 engines (pre-2000) are worst, but 2002 models still carry transmission and cooling vulnerabilities that can strand you.
Nikasil Cylinder Liner Failure (AJ-V8 Engine)
Occasional · high severityTypical onset: 60,000-100,000 mi
Symptoms: excessive oil consumption (quart every 500-1000 mi), rough cold start with blue smoke, loss of compression in one or more cylinders, check engine light with misfire codes
Fix: Complete engine rebuild or replacement required—bore scoring from sulfur in fuel eroding Nikasil linings cannot be repaired in-place. Factory switched to steel liners late 1999, but some 2000-2002 engines still got Nikasil. Rebuild with steel sleeves or source a later block. 40-60 hours labor for R&R and rebuild.
Estimated cost: $8,000-15,000
Upper Timing Chain Tensioner Failure
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: rattling noise from engine on cold start that fades after 10-20 seconds, sudden catastrophic noise if tensioner breaks—chain slaps guide and can jump timing, check engine light if timing slips
Fix: Replace both primary and secondary tensioners plus guides preventively—plastic components fail from heat cycling. Requires valve cover removal and cam locking tools. If chain jumped, expect bent valves. 12-16 hours labor if caught early.
Estimated cost: $2,500-4,000
Plastic Coolant Crossover Pipe Failure
Common · high severityTypical onset: 50,000-90,000 mi
Symptoms: coolant leak in valley between cylinder banks, rapid overheating, steam from hood vents, coolant level drops with no visible external leak
Fix: The factory plastic crossover pipe in the valley cracks from thermal stress. Requires intake manifold removal to access. Replace with aluminum aftermarket unit along with valley pan gasket and all cooling hoses while you're in there. 8-12 hours labor.
Estimated cost: $1,800-3,200
Transmission Oil Cooler Line Leaks
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: pink fluid puddle under front of car, transmission slipping or delayed engagement, burnt transmission fluid smell, low transmission fluid on dipstick
Fix: Steel cooler lines rust through where they route along subframe, or quick-connect fittings crack. Replace both feed and return lines—don't patch one. Flush transmission and replace filter while system is open. 4-6 hours labor.
Estimated cost: $800-1,400
Throttle Body Coolant Jacket Corrosion
Occasional · medium severityTypical onset: 80,000-130,000 mi
Symptoms: coolant leak at throttle body, rough idle when cold, poor throttle response, coolant smell from engine bay
Fix: Aluminum throttle body housing corrodes internally where coolant passages run. Cannot be repaired—requires replacement throttle body assembly and relearn procedure. 2-3 hours labor.
Estimated cost: $600-1,000
Convertible Top Hydraulic Line Leaks (Convertible)
Common · low severitySymptoms: top operates slowly or stops mid-cycle, hydraulic fluid puddle in trunk, grinding noise from top motor, top will not latch or unlatch
Fix: Rubber hydraulic lines harden and crack—common at crimped ends. System uses special Pentosin CHF-11S fluid. Replace all soft lines preventively, bleed system, check rams for leaks. Top mechanism itself is robust. 6-8 hours labor for full line replacement.
Estimated cost: $1,200-2,000
Fuel Pump and Filter Failure
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: no start condition, stumbling under acceleration, engine dies at operating temperature, whining noise from fuel tank area
Fix: In-tank pump fails, often taking out the filter housing seals. Requires fuel tank drop. Replace pump, filter, and tank seals as assembly. Check fuel pressure regulator and lines while tank is out. 5-7 hours labor.
Estimated cost: $1,000-1,600
Only if you have a $5k emergency fund and confirmed service records showing tensioners, crossover pipe, and Nikasil recall compliance—otherwise you're gambling with a grenade.
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.