How to replace the crankshaft breather valve - pictures

<span>Start by removing the inner plastic intake cover. An 8mm socket and three bolts to undo, then ease it off forwards as shown.</span>

<span>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.</span>

<span>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.</span>

<span>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.</span>

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

<span>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).</span>

<span>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.</span>

<span>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.</span>

<span>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.</span>

<span>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.</span>

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

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

<span>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.</span>

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

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

<span>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.</span>

<span>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.</span>

<span>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.</span>

<span>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.</span>