UNDER-BONNET CHECKS & FILTERS

10 CHECK PAS FLUID

The power steering fluid should be checked when its temperature is around 20°C. The reservoir is next to the coolant expansion tank. Unscrew and remove its cap, wipe the dipstick with a clean rag, then dip and extract it again, checking the markings for maximum and minimum. Top up with CHF11S.

11 TOP UP SCREENWASH

The screenwash reservoir’s filler neck is located on the offside rear corner of the engine bay and is labelled. Prise off the cap and top up with a mixture of screenwash and water. Do not use washing-up liquid as it can congeal and risks blocking the pipework.

12 FIND THE CABIN FILTERS

The two cabin filters are hidden under a plastic grille on the nearside rear of the engine bay. Using a 13mm spanner or socket, undo the four plastic quick-release nuts (they require less than a quarter turn anticlockwise to release each one), peel off the rubber seal along its front edge, then lift out the grille.

13 REMOVE CABIN FILTERS

Slacken another three 13mm plastic quickrelease nuts around the cabin filter housing, detach the electrical plug from the side of the housing, then manoeuvre the housing out of the engine bay and turn it upside down to be able to see the two cabin (pollen) filters.

14 REMOVE ANY DEBRIS

Look inside the bulkhead/engine bay area where the cabin filters are fitted and extract any dirt. A vacuum cleaner is the best means of removing dirt. Our X5 seemed to have years of dried leaves and cobwebs. This can block drain holes and, if it gets damp, cause corrosion.

15 REPLACE CABIN FILTERS

Unclip the sides of each cabin filter (two clips on each end) to extract them. They can be quite brittle, but be careful not to break the sides of the housing. Clean any dirt from inside the housing. Fit the new cabin filters, making sure they click into position. Refit the housing and plastic grille. Our new Bosch cabin filters cost £33.50 from CAAR.

16 CHECK THE BRAKE FLUID

The brake fluid reservoir is located under a plastic grille on the offside rear corner of the engine bay. It’s the same type of grille as the one covering the cabin filters, so remove it by releasing four 13mm plastic nuts and prise off the rubber seal. Unscrew the brake fluid reservoir cap and test it for moisture content. If necessary, top up with DOT 4 brake fluid.

17 GEARBOX UNDERTRAY

The plastic rearmost undertray is secured with eight 8mm bolts. Once removed, this provides access to the gearbox. If you are renewing its oil and filter, the undertray to the nearside of it should be dropped down by undoing more 8mm bolts.

18 GEARBOX OIL & FILTER

BMW claim the X5’s automatic gearboxes

(ZF and GM) are sealed for life, but some independent specialists recommend renewing the oil and filter every 60,000 miles. Our X5 has a ZF gearbox fitted. The first job in renewing the oil and filter, before letting the old oil out, is to make sure the filler plug can be slackened using an 8mm Allen key bit.

19 DRAIN THE GEARBOX OIL

Undo the plastic drain plug with a 10mm Allen key. If it rounds off, use a hammer and chisel to unscrew it. The entire sump pan needs to be replaced as it incorporates a new oil filter. Remove the drain plug and leave the oil to drain for several minutes.

20 RELEASE CROSSMEMBER

A crossmember obstructs access to the rearmost Torx T30 screws that secure the rear of the gearbox sump pan, but its mounting bolts can be undone to help move it out of the way. Start by undoing the six 16mm bolts that secure it to the underside of the X5.

21 CROSSMEMBER NUT & BOLT

There’s an 18mm nut and bolt that holds the crossmember in position. The nut can be awkward to access and may require a swan-neck spanner to hold it. Undo and extract the long 18mm bolt. The crossmember should now be loose and can be moved aside enough to access the rearmost T30 screws along the gearbox sump pan.

22 UNDO TORX T30 SCREWS

There are 21 Torx T30 screws fitted around the outer edge of the gearbox sump pan. Slacken all of them before proceeding to remove them completely. The rearmost screws might need a Torx T30 screwdriver to access them. Oil may start to drip out when the sump pan becomes detached.

23 GEARBOX SUMP PAN

Have a large drain bowl positioned below the sump pan when it’s ready to be dropped down. Once released, ensure the old sump and new one are the same (the filter is part of it). Clean the mating surface on the bottom of the gearbox, but be careful not to damage any of the electrics and other components.

24 FIT NEW SUMP PAN

Remove any protective covers from the new sump pan, then fit it into position and refit four of the Torx T30 screws to each corner by hand. Continue refitting all of the remaining screws, gently and progressively tightening them from the inside out. Finally, tighten them all to 10Nm.

25 REFILL GEARBOX OIL

Refill the gearbox via the filler plug using a suitable semi-synthetic ATF – the Lucas oil shown here costs £32.25 for five litres from CAAR. When it’s full, refit the filler plug, run the engine up to temperature and work through the gears (don’t drive the car), then select Park, leave the engine running, and check the oil level via the filler plug, topping up if necessary.

26 ENGINE SUMP UNDERTRAY

The steel undertray fitted beneath the engine oil sump can be removed to check for oil leaks. It’s secured with six 16mm bolts. The front plastic undertray, secured with several crosshead screws, can also be taken off to allow access to the front diff.

27 DRAIN ENGINE OIL

Undo the 17mm oil sump drain plug and collect the old engine oil in a drain bowl or container. Leave it to drain for several minutes. The sump plug can be reused, but its copper washer must be renewed. Some oil filters are supplied with a new washer, as shown here (inset) with this Bosch oil filter, which costs £5.95 from CAAR.

ENGINE & TRANSMISSION OILS 28 REMOVE OIL FILTER

While the engine oil is draining, renew the oil filter. From within the engine bay, remove the nearside induction pipe between the slam panel and the air filter housing. Use a 32mm socket, extension bar and ratchet to undo the oil filter housing, then carefully lift it out of the engine bay.

29 REPLACE OIL FILTER

Extract the old oil filter from the filter housing and replace the rubber seal around the thread of the housing. Fit a new oil filter into the housing, making sure it clicks into position. Refit the housing with its new filter, tightening it to 25Nm.

30 REFILL WITH 5W-30 OIL

Refit the engine oil drain plug with a new copper washer – our M12 drain plug was tightened to 25Nm. Refill the engine with 7.5 litres of 5W-30 fully-synthetic oil. We used Lucas oil, supplied by CAAR, costing £41.50 for five litres. Check the level on the dipstick, run the engine to check for leaks and ensure the oil pressure warning light goes out. Switch off, check the level and top up if required.

31 DRAIN THE FRONT DIFF

Check you can undo the front diff’s filler plug (14mm Allen key), which is accessed via the nearside front wheelarch (remove a plastic cover by undoing a few 8mm bolts). The drain plug is on the underside of the front diff and requires a 14mm Allen key to undo it. Drain the oil into a container.

32 REFILL FRONT DIFF

Refit the front diff’s drain plug. Use a squeezy bottle with extension, or a pump to refill the front diff with 75W-90 synthetic gear oil via the filler plug. The Lucas oil shown here costs £12.50 per 946ml from CAAR. When the oil starts to drip out of the filler hole, refit the plug and tighten it to 60Nm.

33 DRAIN TRANSFER BOX

The transfer box is located towards the centre of the X5. Undo its 14mm Allen key drain plug on its rear, and also remove its filler/inspection plug on the front (it has the same sized head). After draining, refit the drain plug and refill with a suitable transfer box fluid via the filler hole until it drips out.

34 RENEW REAR DIFF OIL

The oil in the rear diff has to be withdrawn using an oil suction pump as there’s no drain plug, only a filler/inspection hole. Undo the 14mm Allen key plug, then extract the old oil. Refill with a squeezy bottle until it starts to drip out. Use the same oil as the front diff. Refit the filler plug and tighten to 60Nm.

35 FIND THE FUEL FILTER

The fuel filter is located underneath the X5, close to the centre, but offset to the nearside. Remove the two 10mm bolts that clamp the body in place. Extract the large horseshoe clip at the back of the fuel filter and have a drain bowl ready underneath. Undo the Jubilee clip securing the fuel hose at the front and release the filter. We fitted a new Bosch fuel filter, which costs £22.25 from CAAR.

36 FIT A NEW FUEL FILTER

Make sure the new fuel filter is the same shape and size as the old one. Transfer the two sleeves on the old filter to the new one (the clamp fits around them). Fit the new fuel filter, attaching the hose at the front and the larger connection at the rear. Refit the horseshoe clip and 10mm bolts. Switch on the ignition to run the fuel pump and prime the filter, then start the engine.

BRAKE & SUSPENSION CHECKS 37 CHECK FRONT SUSPENSION

Using a pry bar, check for excessive play in the bushes for the front track control arms (banana-shaped), the bottom coilover mount and the balljoint for the upper wishbones. Visually inspect each front coil spring – they are known to fracture. Wiggle each drop link and the anti-roll bar.

38 REAR SUSPENSION

With air suspension at the rear, there’s not much to check, except the rear dampers for leaks, and for wear in the anti-roll bar, its drop links, and the suspension arm bushes.

39 CHECK FRONT BRAKES

The front brakes can be visually inspected without having to strip them. Look at both sides of the brake disc for excessive wear and corrosion. Look through the back of the caliper to check the thickness of the inner pad. Check the outer pad by looking down onto it, and check the brake flexi-hose for leaks and damage.

40 STRIPPING THE BRAKES

If you’d prefer to strip, inspect and clean the brakes, then undo the two 7mm Allen key slider bolts. On the rear brakes, extract the metal spring clip that’s fitted against the outer brake pad, and prise off the caliper.

41 CLEAN CARRIER & PADS

Extract the brake pads, and avoid damaging any of the wear sensors. If the pads can be reused, clean their edges with a wire brush and spray them with brake cleaner. Clean inside the caliper carrier where the top and bottom edges of the pads sit, spraying brake cleaner to dampen any brake dust.

42 REASSEMBLE THE BRAKES

Dry-fit the pads and refit the caliper. Gently clean the 7mm Allen key slider bolts and apply a light coating of high-melting-point grease to them. Refit and tighten to 30Nm. Refit the outer pad spring clip on each rear brake. Slowly pump the brake pedal a few times to settle the pads in the caliper.