Question 1

Sill corrosion (structural)

Accepted Answer

Outer sills bubble and perforate. Inner sills rot silently behind trim. The car's rigidity decreases, doors sag, gaps become uneven, and the body flexes over bumps. Water enters the sill box sections through blocked drain holes, failed door seals, and stone chip damage. The inner sill rots first, hidden from view. By the time the outer sill shows rust, the inner structure may be gone. Full sill replacement, outer and inner. The car must be properly supported (ideally on a jig) during the work to prevent distortion. Replacement panels are available for all series. Budget $4,000-8,000 AUD for professional sill repairs on both sides.

Question 2

Floor pan corrosion

Accepted Answer

Floor pans rot from underneath or from above (water sitting under carpets). In severe cases, you can see the road through the floor. Water enters through failed windscreen rubbers, door seals, heater matrix leaks, and blocked drainage. Sound deadening material holds moisture against the steel. Carpet and underlay hide the damage until it's severe. Cut out the rot, fabricate or buy replacement floor sections, weld in. All carpet, underlay, and sound deadening must come out for proper inspection and repair. Budget $3,000-8,000 AUD depending on extent.

Question 3

Rear wheel arch and lower rear quarter corrosion

Accepted Answer

Rust appears at the bottom of the rear wings, around the wheel arches, and in the lower panels between the wheels and boot. Stone chips, trapped mud, inadequate drainage, and the general tendency of British steel to rust when given the slightest encouragement. Cut and replace affected panels. Repair sections are available. Budget $1,500-4,000 AUD per side depending on severity.

Question 4

Boot floor and spare wheel well corrosion

Accepted Answer

The boot floor rusts through, the spare wheel well fills with water, and the rot spreads to surrounding panels. Boot lid seal failure, blocked drain holes, condensation, and (on some cars) battery acid leakage from the boot-mounted battery. Replace the boot floor section. Check and replace the boot seal. Clear all drains. Relocate the battery if acid damage is an issue (some owners move it to the engine bay). Budget $1,500-3,000 AUD.

Question 5

Front wing corrosion

Accepted Answer

Bubbling around headlights, indicator mounts, and the bottom edges of the front wings. Stone chips compromise paint, water gets behind the inner wing, and the bottom edge collects dirt and moisture. Replacement front wings are available for all series. It's a bolt-on panel, so replacement is straightforward. Budget $1,000-2,500 AUD per side including paint.

Question 6

XK engine oil leaks

Accepted Answer

Oil weeps from cam covers, timing chain cover, sump gasket, and rear main seal. The engine bay is perpetually oily. Oil drips on the exhaust and creates smoke. The XK engine uses old-style gaskets (cork, paper, and early-type lip seals) that deteriorate with age and heat cycling. The casting surfaces are rough by modern standards, making perfect sealing difficult. Replace gaskets systematically. Start with the cam covers (easy access, cheap gaskets), then the timing cover, then the sump. The rear main seal requires gearbox removal, do it when the gearbox is out for any other reason. Use modern gasket materials and sealants. Accept that a slight weep is normal, aim for "no drips," not "factory fresh."

Question 7

Cooling system inadequacy

Accepted Answer

Engine runs hot, particularly in traffic or on warm days. Temperature gauge climbs, coolant may boil over, heater blows hot when it shouldn't. The XK engine was designed when cars moved constantly and relied on airflow for cooling. In modern stop-start traffic, the cooling system is marginal. Radiators clog with scale, thermostats fail, water pumps lose efficiency, and fan belts slip. Australian heat makes everything worse. Comprehensive cooling system service: flush and recore (or replace) the radiator, new thermostat, new water pump if weak, check fan belt tension, and consider an electric fan upgrade. Fresh coolant (50/50 mix, not straight water). Budget $1,000-2,500 AUD for a thorough cooling system overhaul.

Question 8

SU carburettor problems (Series 1)

Accepted Answer

Rough idle, flat spots, hesitation, black smoke, fuel smell, poor starting. The twin SU HD6 or HD8 carburettors need regular maintenance, jet needles wear, diaphragms split, float valves stick, and the mixture goes rich or lean. Most mechanics don't understand SUs and make things worse. Strip, clean, and rebuild both carburettors. Replace needles, jets, diaphragms, and float valves. Set float heights. Synchronise with a proper flow meter. Budget $400-800 AUD for rebuild kits and a few hours of patient work.

Question 9

Fuel injection issues (Series 2 and 3)

Accepted Answer

Hard starting, rough idle, hesitation, stalling, poor economy. Early Lucas fuel injection (Series 2) is primitive and parts are getting scarce. Later Bosch injection (Series 3) is more reliable but still has age-related issues, injectors clog, sensors drift, wiring degrades, and vacuum lines perish. Diagnose systematically. Check for vacuum leaks, test the coolant temperature sensor and other inputs, clean or replace injectors, replace perished vacuum hoses. The Bosch system on the Series 3 is well-understood and parts are available. Budget $500-2,000 AUD depending on what's needed.

Question 10

Head gasket failure

Accepted Answer

Coolant loss, white smoke from exhaust, overheating, mayonnaise under the oil filler cap. The aluminium cylinder head expands at a different rate to the iron block. Overheating events, age, and repeated thermal cycling cause the gasket to fail. The XK engine's long head and six cylinders create a large gasket surface area that's vulnerable to distortion. Head off, gasket replaced, head pressure-tested and skimmed if warped. Use quality gaskets and follow the correct torque sequence. Budget $2,000-4,000 AUD.

Question 11

2.8-litre engine problems

Accepted Answer

Excessive vibration, bearing failure, overheating, poor performance. The 2.8 was a de-stroked version of the 4.2 with altered crankshaft and reduced capacity. The shorter stroke created balance issues and increased stress on the bottom end. The engine is also underpowered for the heavy XJ body, leading to over-revving and premature wear. Swap to a 4.2. Seriously. The 2.8 is a fundamentally compromised engine that's not worth rebuilding when 4.2 units are plentiful. A 4.2 swap requires a compatible bell housing and some wiring changes but is well-documented.

Question 12

Borg-Warner BW66 automatic (early cars)

Accepted Answer

Harsh shifts, slipping, delayed engagement. The gearbox overheats under sustained load. The BW66 is an adequate but uninspired gearbox that doesn't cope well with age or abuse. Fluid degrades, bands wear, and the torque converter loses efficiency. Regular fluid and filter changes extend life. When it fails, consider upgrading to a GM TH400, conversion kits are available for all XJ variants. Budget $3,000-5,000 AUD for a TH400 conversion.

Question 13

GM TH400 automatic (later cars), reliable

Accepted Answer

Question 14

Power steering system leaks

Accepted Answer

Power steering fluid on the garage floor, heavy steering, groaning from the pump. Rack seals age and weep. Hose connections corrode. The pump wears internally. Power steering fluid degrades and loses its lubricating properties. Replace leaking hoses first (cheap, easy). If the rack is leaking, a reconditioned unit is the most cost-effective solution. Replace the pump if it's noisy. Budget $1,500-3,000 AUD for a comprehensive power steering overhaul.

Question 15

Lucas ignition failure (Series 1 and 2)

Accepted Answer

Misfiring, rough running, hard starting, random stalling. The car runs on five cylinders or fewer. The Lucas ignition system uses points, condenser, distributor cap, and rotor arm, all of which wear and fail. Moisture gets into the distributor in damp conditions. The condenser fails without warning. Fit an electronic ignition conversion (Pertronix or similar). It's the single best modification you can make to a Series 1 or 2 XJ6, better starting, smoother running, more reliable. Costs $200-400 AUD and takes an hour. Keep the original parts as spares.

Question 16

Alternator and charging system failure

Accepted Answer

Battery goes flat, warning light stays on, instruments dim at idle, car won't start. Early cars had Lucas alternators (or generators on the very earliest models) that fail with age. Voltage regulators burn out. Wiring connections corrode and add resistance. Test the charging system output. Replace the alternator if output is low. Clean all connections, especially the main battery cables and earth straps. Upgrade to a modern high-output alternator if the original is shot. Budget $300-800 AUD.

Question 17

Electric window failure

Accepted Answer

Windows won't go up or down, move slowly, or stop halfway. Window motor brushes wear. Regulators seize or strip. Wiring connections corrode. Switches wear internally. Diagnose whether it's the switch, the wiring, or the motor. Replace the failed component. Motors are available (both new and reconditioned). Budget $200-500 per window.

Question 18

Instrument gauge failures

Accepted Answer

Temperature gauge, fuel gauge, or oil pressure gauge reads incorrectly or not at all. Warning lights illuminate randomly. The Smiths instruments use voltage stabilisers and sender units that fail with age. The printed circuit board behind the instrument cluster develops cracks. Earth connections corrode. Check the voltage stabiliser first (it regulates the supply to the gauges). Test sender units. Inspect and repair the printed circuit board. Specialist instrument repairers can overhaul the complete cluster. Budget $300-800 AUD.

Question 19

Central locking and door lock failures

Accepted Answer

Central locking won't operate, or works on some doors but not others. Key won't turn in the door lock. Vacuum-operated actuators (Series 2 and 3) fail when diaphragms split or vacuum lines perish. Lock barrels wear. Microswitches fail. Check the vacuum supply first. Replace perished vacuum lines. Replace failed actuators. Rebuild or replace worn lock barrels. Budget $200-600 for a complete central locking overhaul.

Question 20

Front suspension bush wear

Accepted Answer

Clonking over bumps, vague steering, uneven tyre wear, the car wanders at motorway speed. The double-wishbone front suspension uses rubber bushes that harden and crack with age. Ball joints wear. Anti-roll bar links deteriorate. Replace all bushes, ball joints, and anti-roll bar links. Polyurethane bushes are available as an upgrade. A complete front suspension refresh runs $800-2,000 AUD in parts, plus labour.

Question 21

Rear suspension compliance mount failure

Accepted Answer

Vague rear end, clunking, rear tyre wear. The back of the car feels disconnected from the front. The independent rear suspension uses large rubber compliance mounts (cages) that deteriorate with age. They're critical to maintaining correct rear geometry. Replace the compliance mounts. It's a significant job involving rear subframe work. Budget $1,500-3,000 AUD.

Question 22

Steering rack wear and leaks

Accepted Answer

Play in the steering, vague centre feel, clonking on turn, power steering fluid leaks. The rack and pinion wears over high mileages. Power steering seals fail. Mounting bushes deteriorate. Reconditioned racks are available and are the most cost-effective solution. Replace mounting bushes at the same time. Budget $1,500-3,000 AUD.

Question 23

Damper (shock absorber) deterioration

Accepted Answer

Wallowing ride, excessive body roll, the car fails to settle over bumps, uneven tyre wear. Dampers lose their effectiveness over time. The XJ6's relatively soft suspension relies heavily on good dampers to control body motion. Replace all four dampers. Aftermarket options (Bilstein, Koni) are often better than the originals. Budget $800-1,500 AUD for a set of quality dampers.

Question 24

Brake servo failure

Accepted Answer

Very hard brake pedal, poor stopping performance. The car feels like it has no brakes. The vacuum servo diaphragm fails, the check valve sticks, or vacuum lines leak. Test the servo by pressing the brake pedal with the engine off, then starting the engine, the pedal should drop slightly. If it doesn't, the servo is faulty. Rebuild or replace. Reconditioned servos are available. Budget $500-1,000 AUD.

Question 25

Caliper seizure

Accepted Answer

Uneven braking, pulling to one side, excessive heat from one wheel, brake drag. Brake caliper pistons seize from corrosion, especially if the car has been sitting for extended periods. Old brake fluid absorbs moisture, which accelerates internal corrosion. Rebuild or replace the affected caliper. Replace all brake fluid with fresh DOT 4 or DOT 5.1. Inspect all calipers, if one has seized, the others are likely close behind. Budget $300-600 per caliper.

Question 26

Brake disc warping

Accepted Answer

Judder through the steering wheel or brake pedal under braking. Discs warp from heat, particularly if the brakes are used hard then the car is stopped (heat concentrates at the pad contact point). Age and corrosion compound the problem. Machine the discs if they're within thickness limits. Replace if they're too thin or cracked. Budget $200-500 per axle including pads.

Question 27

Air conditioning system failure

Accepted Answer

A/C doesn't cool, compressor won't engage, strange noises from under the bonnet. The A/C system is complex and every component degrades with age, compressor seals leak, condensers corrode, evaporators fail, and the control system (vacuum-operated flaps on many XJ6 models) deteriorates. Early systems used R12 refrigerant, which requires conversion to R134a. Full A/C system diagnosis and overhaul. Retrofit to R134a if still on R12. Replace failed components. Budget $2,000-5,000 AUD for a comprehensive A/C restoration.

Question 28

Heater matrix leak

Accepted Answer

Coolant smell in the cabin, damp carpet on the passenger side, fogged windscreen. Coolant level drops with no external leak. The heater matrix, a small radiator inside the dashboard, corrodes and develops leaks. Old coolant or running plain water accelerates the corrosion. Replace the heater matrix. Unfortunately, this usually requires significant dashboard disassembly. Budget $500-1,500 AUD including labour. Run proper coolant mix after replacement.

XJ6 (Series I-III)

XJ6 (Series I-III) known problems