Make your Freelander breathe more efficiently - pictures

Next, do the same for the rear air filter cover. This time there are five Hex bolts (5mm), and the oil filler cap to remove.

Remove the two bolts hidden down the back, one at each side. A small extension or wobble bar on the ratchet is just the job.

Cover removal is tricky. Ease the pipework away on the right hand side, then angle it like this, to clear the intake pipe on the right.

At this stage, immediately replace the oil filler cap. Debris falling in there will definitely not help, especially a dropped bolt!

Undo three security bolts on the wiring loom mounts, and move it clear (6mm socket will turn them if you’re careful, they aren’t very tight).

The PCV cover is then exposed, between the air filter and the injectors. Remove the four Hex bolts, with a 5mm Hex socket and ratchet

Prise the cover off, and lift it out. The existing filter will come away with it, along with a small fixing arm. Take care – this can easily fall off.

New BMW oil separator and cover is on the left, and the old filter on the right. This one isn’t too bad, but it is definitely due a change.

Also note the sprung valve in the cover. See how the old one attracts oil. This can be rinsed in petrol, but a new one will always be better.

Remove the two old seals in the engine housing. BMW conveniently decided to fit neat tabs to aid grip for simple removal.

Clear any debris and refit the two new seals, supplied with the oil separator and cover. Locate them into their recesses.

Drop the oil separator into the new housing and push down (it only goes one way), then lower the assembly into position on the engine.

Clearance is tight on two small hoses by the injector loom. Have some patience, and with care the cover can be eased past them.

Push it down to ensure it locates without pinching any wiring/hoses, then re-tighten the four Hex bolt fittings for an airtight fit.

Locate the injector wiring loom over the top of the PCV cap, then refit the loom’s three security screws, taking care not to burr the heads.

Remove the oil cap and refit the tricky air intake cover and Hex bolts. The right hand feed into the engine intake is the most difficult.

Refit the inner plastic engine cover. It helps to remove the bolts on this one, to help feed the rear lip under the air intake cover.

Finally, refit the three 8mm bolts. The left hand one goes into the crankcase: if you get a slight oil leak here, this one isn’t tight enough.