UNDERBONNET CHECKS

1 REMOVE ENGINE COVER

A large plastic cover is fitted over the top of the engine, so it requires removal to get to components below. It’s secured at the sides with a couple of 13mm bolts. Watch the dipstick doesn’t get caught when lifting it off.

2 CHECK PAS FLUID

Wipe around the cap of the power steering fluid reservoir before unscrewing it. Wipe the dipstick on the underside of the cap, dip and extract it to check the level – there are markers for high and low. Top-up with Dexron II or whatever has been used before.

3 CHECK BRAKE FLUID

The brake fluid reservoir is translucent, so shine a torch on the side to check the level against the MIN and MAX markers. Top-up with DOT 4 brake fluid, or whatever has been used before.

4 TEST COOLANT

The coolant reservoir is at the back of the engine bay (offside). Check the level by shining a torch on the side (there’s a marker for when the coolant is cold). Top-up with whatever has been used before. If you have an antifreeze hydrometer, check its freezing capacity.

5 SQUEEZE HOSES

Look for the coolant hoses in the engine bay and check their condition by squeezing them (make sure the engine is cold first). Check any spring or Jubilee clips that secure the ends of the hoses. Renew if they are rusty-looking.

6 CHECK CLUTCH FLUID

The clutch fluid reservoir is hidden between the brake servo and the coolant reservoir. Carefully release its cap and look inside to check the fluid level. Top-up with whatever fluid has been used before.

7 REMOVE DIRT & MOISTURE

Look around the engine bay for trapped dirt and moisture that can result in corrosion.

The small amount of debris shown here could easily result in electrical problems for the nearby plug if it becomes wet and spreads.

8 CHECK SCREENWASH

Top-up the windscreen washer fluid reservoir with screenwash. Operate the windscreen wipers to check they spray over the glass. Test the rear wiper as well (if fitted). Afterwards, inspect the condition of the wiper blades.

9 GREASE BONNET RELEASE

Spray grease over the locking mechanism for the bonnet (on the top of the slam panel). Apply a little grease to all the door locks and hinges. Operate them several times to work the grease inside.

10 REPLACE AIR FILTER

Release two metal clips for the air filter housing lid and two more for its induction hose, then remove the lid. Extract the old air filter, clean inside the housing, fit a new air filter and reassemble.

11 INSPECT AUX BELT

The auxiliary drive belt can be inspected from above the engine bay. Look for cracks across the ribs and fraying along the edges. It can also be inspected from underneath the front of the vehicle.

12 INSPECT ENGINE MOUNTS

The nearside and offside engine mounts can be checked by looking at them from the side of the front wings. Look for perishing of the rubber and corrosion.

13 DRAIN ENGINE OIL

From underneath the vehicle, undo the 17mm drain plug and collect the old oil in a container. Once it has drained, refit the drain plug with a new copper washer and tighten it to 23Nm.

14 CHANGE SPIN-ON FILTER

Use a filter strap to undo the old spin-on oil filter (space is tight). Carefully remove it, placing cloths underneath to catch any oil. Add a smear of oil to the seal of the new filter and fit it by hand. It’s awkward to tighten by hand.

15 FIND CENTRIFUGAL FILTER

A second oil filter is located above the spin-on filter. First, undo two 10mm bolts for a top cover and remove it. Change the seal around this cover (a new one should be supplied with the filter).

16 CHANGE CENTRIFUGAL FILTER

Extract the centrifugal oil filter and fit a new one. Refit the top cover with its new seal and refit the two 10mm bolts. The top cover can only be fitted one way round.

17 REFILL 5W-30 ENGINE OIL

Measure eight litres of 5W-30 engine oil (the recommended grade may be different, depending on climate) and pour it into the engine via the filler cap. Check the level on the dipstick and top-up if required. Run the engine to ensure the oil pressure light goes out on the dashboard, then switch-off, look for leaks and check the level again on the dipstick, topping-up if necessary.

18 CHECK LIGHTS

Operate all exterior lighting to look for failed bulbs. Most bulbs can be accessed from the outside by undoing a couple of crosshead screws for the lenses. The headlight bulbs are accessed from inside the engine bay.

19 CHECK TYRES

Inspect the condition of the sidewalls for all the tyres, including the spare (if fitted), looking for signs of perishing and damage. Measure the tread depth and look for uneven wear, which may indicate wheel alignment issues or worn suspension.

20 TEST SEAT RUNNERS

Check the two front seats can be adjusted forwards and backwards on their runners and that they lock into position. If the seats are difficult to move, try spraying a light grease over the runners to help free them up.

21 CHECK PEDAL RUBBERS

Inspect the condition of the rubber pads fitted to the brake, clutch and accelerator pedals. These pedal rubbers can be replaced if they are worn and don’t provide sufficient grip.

23 TEST BATTERY

Check the battery’s voltage with a multimeter or battery tester. Make sure the terminals are securely fitted and not corroded. Apply a smear of petroleum jelly to them. Check the battery is securely located.

22 FIND THE BATTERY

Pull the front edge of the passenger seat base upwards to release it from where it’s clipped into position, then pull it forwards. Release a clip at the front (below where the front edge of the seat was fitted) for a metal cover that sits under the seat base. Slide it forwards, then peel back a fabric cover to see the vehicle battery.

24 CHECK STEERING

The Defender uses a steering box, so check the linkage from underneath the front of the vehicle, looking for splits in the dust covers of the balljoints and general damage. Use a pry bar to check any bushes and also check the steering track arm.

25 INSPECT FRONT BRAKES

The front brake discs and pads can be inspected from underneath the vehicle. Measure the thickness of the brake disc (minimum 12mm for solid discs and 22mm for ventilated). Use a brake pad gauge to measure the thickness of the pads’ friction material.

26 CHECK SPRINGS & FLEXIS

Each front brake flexi-hose can be inspected from underneath – look for leaks and perishing of the rubber hose. Visually inspect the front coil springs, looking for fractures.

27 LOOK FOR OIL LEAKS

Look around the underside of the engine, gearbox and front diff for signs of oil leaks. Clean any oil residue to be able to recheck this area in the near future and see whether an oil leak needs to be addressed.

28 CHECK FRONT DIFF OIL

Use a ½in square ratchet or similar tool to undo the refill/inspection plug on the side of the front differential. The oil level inside should be just below the hole. If it needs topping-up, use 90W or whatever has been used before. If the oil needs draining, there’s a ½in square drain plug on the underside of the diff housing.

29 CHECK SWIVEL HUBS

Undo the filler plug on the top of each front swivel hub using a 3/8in square ratchet or suitable tool. Top-up with the recommended grease. The swivel hubs are prone to leaking, so need to be routinely topped-up.

30 CHECK TRAILING ARM BUSHES

Use a pry bar to look for excessive movement in the front and rear mounting bushes for the front and rear trailing arms (also called radius arms). Visually inspect the rubber bushes for perishing and splits.

31 WIGGLE PROPSHAFT UJS

Try to rotate the propshafts back and forth to feel for excessive movement in the universal joints. There are two propshafts underneath the vehicle, which can be inspected at either end where the universal joints are fitted.

32 GREASE POINTS

If there are grease nipples on the propshafts and their universal joints, pump some multipurpose grease through them (a couple of pumps of the grease gun is usually sufficient).

33 CHECK GEARBOX OIL

The manual gearbox has a Torx T55 refill/ inspection plug on the side. The level should be below the filler hole. Top-up with Texaco MTF 94 or whatever has been used before. If the oil needs to be drained, there’s a 3/8in square drain plug below the filler plug.

34 CHECK TRANSFER BOX OIL

The transfer box holds 2.3 litres of 75W-90 gear oil. Use a ½in square ratchet or similar tool to undo the refill/inspection plug on the side to check the level inside. If the oil needs to be drained, the drain plug also has a ½in square insert.

35 CHECK TRANSFER MOUNTS

Visually inspect the condition of the rubber for the transfer box mount and also the condition of the gearbox mount on the opposite side. Look for signs of perishing and cracks.

36 INSPECT EXHAUST

Check the condition of the exhaust system, ensuring any rubber hangers are securely fitted and not perished or broken. If it’s safe to run the engine and look underneath the vehicle, check for leaks.

37 REAR SPRINGS AND DAMPERS

Visually inspect the condition of the rear coil springs, looking for fractures. Check the condition of the lower mount for each telescopic damper, looking for perished and cracked rubber. Look around the damper for leaks.

38 FUEL FILTER

The fuel filter can be accessed through the offside rear wheelarch. Check the fuel lines for leaks and make sure its protective cage is intact. If it needs to be replaced, the cage cannot be removed, so the filter’s fuel pipes must be disconnected and the filter lifted out.

39 LOOK FOR RUST

Check along the underside of the bodywork for corrosion, especially between the outer sills and the chassis rails where outriggers and mounting bracketry can become covered in road dirt. Poke a screwdriver through any drain holes in the chassis rails.

40 CHECK REAR DIFF OIL

The rear diff is identical to the front diff when it comes to checking its oil level, topping-up and draining. It also holds 1.7 litres of 90W oil and requires a ½in square ratchet or similar tool to undo its refill/ inspection plug and drain plug.

41 CHECK REAR BRAKES

The thickness of the rear brake discs and the friction material of the brake pads can all be measured from underneath the rear of the vehicle. Check the condition of the disc guards, which can become coated in road dirt and consequently may be rusty.