IsItAGoodCar
Reliability Guide

Common Problems with the
2000 Jaguar XK8 / XKR (X100)

We've identified 3 known issues that can affect the 2000 Jaguar XK8 / XKR (X100). 3 of these are serious faults that could be expensive to repair.

3
Known Issues
3
Serious
0
Moderate
0
Minor

All Known Issues

Plastic Secondary Timing Chain Tensioner Failure

SeriousEngine

Early 4.0-litre AJ26 and AJ27 V8 engines utilized first- and second-generation plastic-bodied secondary timing chain tensioners. Over repeated heat cycles and exposure to acidic engine oil, the plastic body develops stress fractures and the plastic shoe breaks off. This allows the secondary timing chain to slacken and skip teeth on the camshaft sprockets, causing piston-to-valve collision that results in bent valves and catastrophic engine destruction.

Est. Repair Cost: £800–£1,500
Warning Signs:

Loud metallic rattle or clattering noise from the front timing cover on cold startup, Rough erratic idling with misfire codes P0300 to P0308 stored in the engine ECU, Sudden loss of compression and failure to restart after a cold start attempt

What to Inspect:
  • Inspect service history for documented invoice proof of metal-bodied Gen 3 tensioner retrofits
  • Remove the right-hand (bank 1) camshaft cover to visually inspect tensioner body composition
  • Listen attentively with a mechanic stethoscope to the upper timing covers during cold startup
Verified by IsItAGoodCar Research TeamUpdated

Nikasil Cylinder Bore Lining Degradation & Compression Loss

SeriousEngine

Engines produced prior to August 2000 (engine numbers before 0008181043) used nickel-silicon carbide (Nikasil) electro-plated directly onto the aluminium cylinder bores. High sulphur levels in 1990s UK petrol reacted chemically with moisture to form sulphuric acid, eroding the microscopic Nikasil layer. This caused rapid ring wear, severe blow-by, bore wash, and terminal loss of cylinder compression when cold.

Est. Repair Cost: £2,500–£4,500
Warning Signs:

Difficult cold cranking or prolonged turning over before the engine fires, Excessive crankcase pressure and oil mist ejected through the dipstick tube, Heavy oil consumption and blue smoke on deceleration from worn piston rings

What to Inspect:
  • Perform a relative compression check or cylinder leak-down test on all eight cylinders
  • Check the engine block stamping date or look for a dealer warranty steel-linered engine tag
  • Inspect the oil filler neck and breather baffles for excessive blow-by emulsion deposits
Verified by IsItAGoodCar Research TeamUpdated

Rear Suspension Subframe and Chassis Sill Corrosion

SeriousBodywork & Rust

The X100 chassis traps road mud, wet salt spray, and moisture behind the full-length plastic sill covers, inside the rear wheel arches, and across the fabricated rear subframe mounting points. Structural steel inner sills and front footwell floor outriggers corrode from the inside out. By the time bubbling paint appears externally, extensive structural welding is required to meet UK MOT requirements.

Est. Repair Cost: £600–£2,000
Warning Signs:

Crunching or creaking sound when placing a workshop trolley jack beneath factory jacking points, Bubbling paint along lower front wheel arch edges and forward of the rear wheels, UK MOT failure advisory for structural corrosion within 30cm of safety mounting points

What to Inspect:
  • Use a high-intensity inspection torch to probe inner sills and seat belt anchorage floor sections
  • Inspect the rear suspension A-frame mounting plates and crossmember bushes for flaky rust
  • Examine past UK MOT history for repeat advisories regarding underbody and floor corrosion
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2000 Jaguar XK8 / XKR (X100)

  • Demand documented proof that early 4.0-litre AJ26/AJ27 engines have had their fragile plastic secondary timing chain tensioners upgraded to third-generation metal-bodied units.
  • Inspect the structural sills and floorpans thoroughly; corrosion hidden behind the plastic sill kick-plates and around the rear subframe mounts is the leading cause of MOT failure.
  • On convertible models, check the hydraulic hood mechanism for slow operation, green fluid leaks beneath the rear seat, or hydraulic ram hose degradation.
  • Verify automatic transmission servicing; the five-speed ZF 5HP24 (and Mercedes 722.6 on early XKR) requires fresh fluid and filter changes every 50,000 miles despite original sealed-for-life claims.
  • Test the condition of the front suspension wishbone bushes and CATS adaptive dampers; heavy V8 front-end weight rapidly wears lower ball joints and causes uneven front tyre wear.
Check a 2000 Jaguar XK8 / XKR (X100) by Registration