Land Rover Discovery 1 300Tdi faults and fixes

Won't start (diesel)

Diagnose

1. Listen for the fuel shut-off solenoid clicking on the injection pump when the key goes to 'on'.
2. Crack an injector pipe nut and crank: fuel should spit out. Bubbles or nothing means air or no fuel.
3. Work the lift pump priming lever: on a Tdi, if it never builds resistance over two engine revolutions, the linkage has broken.
4. Check each glow plug with a test lamp or resistance meter. Series heater plugs are wired in series, so one failed plug stops them all.
5. Check cranking speed and battery voltage while cranking (should stay above about 10 V).

Fix

1. Bleed the system: filter head bleed screw first, then the pump bleed screw, then crack injector pipes while cranking.
2. Replace failed glow plugs, and the relay or timer if no power reaches them.
3. Replace the lift pump.
4. Replace the fuel shut-off solenoid if it doesn't click with 12 V present.
5. Change the fuel filter; in winter use winter-grade diesel.

Overheating

Diagnose

1. Check coolant level cold and look for leaks with the engine at pressure.
2. With the engine hot, feel the radiator: cold patches mean blocked tubes.
3. Feel the top and bottom hoses as it warms up: the top hose should get hot suddenly when the thermostat opens.
4. Hot engine, stopped: the viscous fan should be hard to turn by hand (use a rolled newspaper, never fingers near a moving fan).
5. Look for constant bubbles in the expansion tank or a sweet exhaust smell (head gasket). A sniffer test (block tester) confirms.

Fix

1. Replace leaking hoses and clips; replace the water pump if it weeps from the drain hole or the bearing has play.
2. Flush or re-core/replace the radiator.
3. Fit a new thermostat and gasket.
4. Adjust or replace the fan belt.
5. Replace the viscous coupling.
6. Head gasket: remove the head, check it for flatness, fit a new gasket (Tdi: match the hole-count marking) and new bolts where required.

Engine oil leaks

Diagnose

1. Degrease the engine, drive 10 miles and look for where the oil starts. Oil runs down and back, so look high and forward.
2. A drip from the bell housing drain hole points to the rear crank seal (or gearbox input seal; gearbox oil smells different).
3. Check the breather and its hoses are clear: a blocked breather pushes oil out of every seal.

Fix

1. Replace the rocker cover gasket, half-moon seals and breather O-ring (Tdi).
2. Fit a new sump plug washer; reseal the sump if needed.
3. Front seal: remove the crank pulley and fit a new seal (Tdi: done with the timing belt).
4. Rear seal: gearbox out. Check the crank for a groove worn by the old seal.

Swivel ball leaking or pitted (coil-sprung)

Diagnose

1. Clean the ball and inspect the chrome for pitting.
2. Check for play at the swivel with the wheel off the ground.
3. Drive slowly on full lock: clicking means the CV joint.

Fix

1. Remove the brake caliper (hang it up, don't strain the hose), hub, stub axle and halfshaft/CV.
2. Remove the swivel pins and swivel housing.
3. Replace the ball if pitted. Fit a new seal kit and swivel pin bearings and set the preload.
4. Refill with one-shot grease (or EP90 on early axles) and refit everything with new hub seals and lock tabs.

Hub seal leak / oil on brakes

Diagnose

1. Check the diff and swivel levels aren't overfilled and the axle breather is clear.
2. Check for bearing play.
3. Once apart, feel the stub axle seal surface for a groove.

Fix

1. Remove the hub. Replace both hub seals and the bearings if worn.
2. Adjust the hub bearing nut and lock with a new tab washer.
3. Replace contaminated brake shoes or pads; you can't clean oil out of them.
4. Coil-sprung: some owners prefer the double-lip RTC3511 seal; check it sits deep enough not to rub and fit it the right way round.

Brakes pull, judder or squeal (disc brakes)

Diagnose

1. Check pad thickness and whether both pads on a wheel wear evenly.
2. Spin each wheel after braking: a dragging wheel has a sticking caliper or hose.
3. Measure disc thickness and look for a lip.

Fix

1. Fit new pads (axle set) and discs if below minimum or warped.
2. Free or rebuild sticking calipers; replace if the bore is pitted.
3. Replace old hoses and bleed with fresh DOT4.

Handbrake won't hold

Diagnose

1. Adjust it first at the back-plate adjuster on the rear of the transfer box.
2. If it still won't hold, remove the drum and look for oil on the shoes.
3. Check the expander moves freely.

Fix

1. Replace the transfer box rear output seal if leaking.
2. Fit new handbrake shoes and clean the drum.
3. Free or replace the expander and its boot.

Death wobble (violent steering shake)

Diagnose

1. With a helper rocking the steering wheel, watch every joint from the box to the wheels for lost motion.
2. Check the steering damper: it should resist evenly both ways.
3. Lever the radius arm and panhard rod bushes for movement.
4. Check swivel preload with the track rod disconnected.
5. Check wheel balance and tyre condition.

Fix

1. Replace worn ball joints (often as a kit).
2. Fit a new steering damper.
3. Replace worn radius arm and panhard rod bushes.
4. Set swivel preload.
5. Tighten the steering box bolts and check the chassis around them for cracks.

Clutch slipping or won't disengage

Diagnose

1. Check the clutch fluid level and look for fluid at the slave cylinder.
2. Pump the pedal: if it firms up, there's air in the system.
3. Slipping in a high gear under load means a worn or oily plate.

Fix

1. Replace the slave or master cylinder and bleed.
2. Gearbox out: fit a clutch kit; fix the rear crank seal at the same time if oily.
3. Series: check the cross-shaft and its pins and bushes while it's apart.

Clunk on taking up drive

Diagnose

1. Twist each propshaft against its flange: any free movement at a UJ means it's worn.
2. Remove a hub cap and drive member and check spline wear.
3. Check mounts.

Fix

1. Replace UJs (or the propshaft) and grease them.
2. Replace worn drive flanges and halfshafts as needed (Series: note 10 or 24 spline).
3. Tighten propshaft bolts.

Battery not charging

Diagnose

1. Measure battery voltage at rest (about 12.6 V) and at 2,000 rpm (about 13.8–14.4 V).
2. Check belt tension.
3. Check the earth straps from battery to chassis and engine to chassis.

Fix

1. Tension or replace the belt.
2. Dynamo: replace brushes or the dynamo, and the control box if its contacts are burnt.
3. Replace or recondition the alternator.
4. Clean and tighten all earth connections.

Rotten rear crossmember or outriggers

Diagnose

1. Tap all over with a hammer: sound steel rings, rotten steel thuds.
2. Pay particular attention to the rear crossmember, spring hangers (Series), outriggers and the rear body mounts.

Fix

1. Replacement crossmembers and outriggers are made for every model; they are cut out and welded in.
2. Remove the rear tub or body tub mounts for access as needed.
3. Paint and inject cavity wax afterwards.
4. Extensive rot: a galvanised replacement chassis may cost less than repairs.

Bulkhead footwells and door pillars rotted

Diagnose

1. Lift the mats and probe the footwell corners.
2. Check the bottom of the door pillars from inside the wheel arch.

Fix

1. Weld in repair panels (footwell, A-pillar foot, top rail sections are all available).
2. Fix the water leaks first: windscreen seal, door seals, vent flaps (Series).

Differential whine or clonk

Diagnose

1. Check the oil level and condition. Milky oil means water.
2. Check pinion flange play: up-and-down movement means bearing wear.

Fix

1. Refill with fresh oil and clear the breather.
2. Replace pinion bearings and seal, or fit a reconditioned differential.
3. Replace a broken halfshaft.

Engine knock

Diagnose

1. Check oil level and pressure with a gauge.
2. Pull each injector lead or plug lead in turn (petrol) or crack each injector pipe (diesel): if the knock changes, it's in that cylinder.
3. A light tapping at half engine speed is usually valve gear: check clearances.

Fix

1. Valve gear: adjust or replace rockers and followers.
2. Bearings: drop the sump and inspect. Bearings and crank regrind, or a reconditioned engine.
3. Don't keep driving a bearing knock; it ends in a broken crank or rod.

300Tdi timing belt walking

Diagnose

1. Remove the wading plug or the cover and look at the belt edge and the backplate for wear.

Fix

1. Fit a quality timing belt kit with new tensioner and idler.
2. Fit the later-type timing cover / backplate where an early one is worn.
3. Set timing with the flywheel and pump timing pins.

Tdi lift pump failed

Diagnose

1. Work the priming lever over two full turns of the engine. If it never resists, the linkage is broken.

Fix

1. Replace the lift pump with a new gasket.
2. Bleed the fuel system.

Water leaks into the cabin (Discovery 1 & 2, Range Rover Classic)

Diagnose

1. Pour water into each sunroof corner and the scuttle: it should run out under the vehicle.
2. Have a helper hose the roof, screen and doors section by section while you look inside with a torch.
3. A sweet smell and greasy mist on the inside of the screen point to the heater matrix, not rain.

Fix

1. Clear drains with strimmer line or compressed air.
2. Reseal or replace the leaking seal or window.
3. Replace the heater matrix.
4. Dry the carpets and check connectors that got wet.