Ford XR8: common faults & what to check

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The 5.4L V8 Barra used in the GT and XR8 models (BF onwards) has a secondary timing chain between the two cam sprockets. These secondary chains and their plastic guides deteriorate over time and mileage. A stretched or broken guide allows the chain to jump, causing timing errors, rough running, and potential valve-to-piston contact on higher-revving examples. Failure often begins with rattling on cold start. Timing chain replacement is labour-intensive on the DOHC V8.

Example of the part — not this vehicle

Where to look: Front of engine – secondary timing chain and upper plastic guides

Parts involved: Timing chain.

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High-mileage Boss 5.4 engines exhibit elevated oil consumption, typically above 1L per 3,000 km. Piston ring land wear and valve stem seal degradation are the primary causes. Blue smoke on overrun or hard acceleration is the visible symptom. This leads to fouled spark plugs, increased fuel consumption, and catalyst contamination. While ring replacement requires a full engine rebuild, valve stem seal replacement can be performed with the head in situ using a compressed-air hold technique.

Parts involved: Catalytic converter.

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The 5.4L DOHC Boss V8 uses variable cam timing phasers (VCT) on both intake and exhaust camshafts. Phaser vanes wear and the locking pins fail to seat under low oil pressure or at low RPM. The characteristic symptom is a loud metallic rattle from the front of the engine at idle or cold start, which may clear as oil pressure builds. Worn phasers can cause retarded cam timing, misfires, and rough running. Replacement of the phaser assemblies and associated VCT solenoids is required. This fault is closely linked to oil change interval compliance.

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The ZF 6HP26 six-speed automatic fitted to FG and FGX Falcon is robust but the electro-hydraulic solenoids controlling gear selection wear and clog at high mileage when fluid is not serviced. ZF specifies lifetime fluid but this is not appropriate for Australian and NZ operating conditions; neglected fluid degrades and deposits varnish on solenoid bores, causing shift hesitation, harsh engagement, and fault codes. Solenoid replacement or valve body rebuild is the usual repair.

Where to look: Automatic transmission valve body, solenoid pack assembly accessible via transmission sump removal

Parts involved: Mechatronic / valve body.

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The BA and BF Falcon fitted with the 5-speed automatic transmission exhibits torque converter shudder — a vibration felt through the drivetrain at light throttle when the converter clutch applies in top gear. The fault is caused by glazed converter clutch friction material and is often temporarily suppressed by a fluid change using friction modifier additive. Persistent cases require torque converter replacement.

Example of the part — not this vehicle

Where to look: Automatic transmission torque converter, lock-up clutch friction material inside converter body

Parts involved: Torque converter.

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The BTR M93LE 4-speed automatic used in AU and early BA Falcons develops worn valve body bores and failing servo pistons over time. Symptoms include harsh or delayed 2-3 upshifts, converter shudder, and slipping under load. The servo bore for the 2nd gear band can wear oval, preventing the band from applying with full force. A valve body recondition or replacement resolves most shift quality issues; worn servo bores require a full rebuild. Fluid and filter service at the correct interval (every 40,000 km) significantly extends service life.

Parts involved: Mechatronic / valve body.

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The Boss 5.0L V8 in the FG GT/GT-P Falcon has a documented tendency toward elevated oil consumption driven by a positive crankcase ventilation (PCV) system that routes oil vapour back through the intake manifold. Over time the PCV hoses and baffle become oil-saturated and can allow liquid oil to be ingested, accelerating combustion chamber deposits and spark plug fouling. Affected engines consume 1 litre per 2,000–3,000 km and may exhibit blue smoke at start-up.

Where to look: Engine valley / intake manifold — PCV hose routing from cam covers to intake

Parts involved: PCV / oil separator.

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The OEM water pump on the Barra NA I6 uses a pressed-steel impeller and a bearing that is susceptible to wear from coolant contamination. Seal failure allows coolant to weep from the pump snout weep hole, which is a pre-failure indicator. Bearing failure produces a rumble or squeal from the front of the engine and can allow the pump to wobble, damaging the timing cover seal. Complete replacement is required. The pump is driven by the serpentine belt on Barra NA engines and is accessible without major disassembly.

Parts involved: Water pump.

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BA and BF Falcon PCMs are prone to internal solder joint cracking and MOSFET failure due to thermal cycling and the PCM's location in the engine bay on some variants. Faults manifest as intermittent no-start, stalling, loss of injector pulse, and fault codes that cannot be cleared. A failed PCM will not communicate with a scan tool. The unit is not serviceable by the owner and requires either a new unit (programmed to the vehicle) or a specialist remanufactured unit. PIN/immobiliser data must be transferred or re-coded on replacement.

Parts involved: Fuel injector.

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Front lower control arm ball joints on the BA through FG Falcon platform are a known wear item with a documented failure rate on higher-mileage examples. Joint failure allows the wheel to change camber unpredictably and in severe cases the joint can separate, causing loss of steering control. A failed joint is a critical safety defect. The lower arm includes the ball joint as a replaceable component on most variants, making repair more affordable than whole-arm replacement.

Example of the part — not this vehicle

Where to look: Front suspension lower control arm, ball joint

Parts involved: Ball joint.

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High-mileage Falcon sedans and wagons, particularly those operated in higher-rainfall or coastal areas of NZ or AU, develop rust in the floor pan around the firewall base, under the rear seat, and along the inner sill sections. Water ingress through door seal degradation and blocked drain holes traps moisture in these areas. While the Falcon is not as rust-prone as Japanese vehicles of similar age, rust in structural sill sections can affect roadworthiness and WOF/RWC compliance.

Where to look: Floor pan, inner sills, firewall base

Parts involved: Body corrosion.

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The FG/FGX Falcon's independent rear suspension uses a stub axle that presses into the rear knuckle, retained by a large nut. The hub bearing integrated into the knuckle wears prematurely — particularly on higher-mileage cars or those used with sustained high rear loads — producing clunking, wheel wobble, and vague rear-end handling. The bearing failure can be rapid once noise begins, and a collapsed bearing can allow significant lateral wheel movement, causing a safety hazard.

Where to look: Rear suspension — both rear knuckles / hub carriers

Parts involved: Wheel bearing.

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The FG/FGX Falcon's independent rear suspension mounts the differential carrier to the subframe via large rubber bushings that deteriorate with age, heat cycling, and aggressive use. When the bushings degrade, the differential can shift under load, causing clunking on throttle application and lift-off, imprecise rear-end feel, and accelerated halfshaft CV joint wear from the resultant misalignment. Performance-oriented or high-mileage examples are most affected.

Where to look: Rear subframe — differential carrier front and rear mounting bushings

Parts involved: Differential.