How to replace a cabin air filter

When to replace a cabin air filter

The cabin air filter is a service item. Your vehicle manufacturer's service schedule says when it is changed: after a distance, after a time, at a particular service, or at whichever of these comes first. As a rough guide: where a supplier in our catalogue states a recommended change interval for a cabin air filter, it is almost always 15,000 km or 20,000 km. Where a supplier states one, the vehicle's page shows the interval among the specifications of the part number; where a vehicle's list is long, it shows specifications for part of the part numbers only. Schedules differ between vehicle manufacturers, and many also set a time limit, so the schedule for your vehicle decides. Many schedules call for an earlier change on vehicles driven in dusty or heavily polluted air. Where the vehicle has a service indicator, follow what the handbook says about it.

Whatever the schedule says, inspect the filter when you notice one of these, and replace it if it is damaged, wet, mouldy or heavily clogged; look for other causes if the filter's condition does not explain what you noticed:

• Less air comes out of the vents than before, even with the blower at a high setting
• The windows mist up more readily or take longer to clear
• A musty or stale smell comes from the vents
• The blower has become louder, or leaves and other dirt come out of the vents

These symptoms have other causes too, such as a fault in the blower or its control, a blocked air intake, a blocked condensate drain or growth on the air conditioning's evaporator, so a new cabin air filter is not a diagnosis of them. Colour alone is a poor guide as well: a filter darkens in normal use, and a filter that looks clean can be due by the schedule.

Replace a filter that is torn, crushed, wet, mouldy or heavily clogged, or whose frame or seal is damaged, whatever its age. Do not wash a cabin air filter, knock it out or blow it out with compressed air unless its maker's instructions expressly allow that for the part: cleaning can damage the filter medium without the damage being visible, and it does not restore an activated carbon layer.

Before you start

On many vehicles the filter sits close to the passenger airbag, a knee airbag or their wiring. Never unplug, pull on or strain a connector or cable of the airbag system, and do not remove a part that carries or covers an airbag. If the vehicle manufacturer's procedure for reaching the filter includes work on a component of the airbag system, leave the job to a workshop.

• Park the vehicle on level ground with the parking brake applied. Switch off the ignition, with the blower and the air conditioning off, and keep the key or remote away from the vehicle, so that nothing can be switched on while you work. On some vehicles the blower can run with the ignition off, for example through auxiliary heating or ventilation or a remote function: switch such functions off and follow your vehicle manufacturer's instructions.
• Find out where the cabin air filter is on your vehicle and how its housing opens. The handbook or the vehicle manufacturer's procedure says where it is. Common places are behind or below the glove box, under the dashboard in a footwell, at the side of the centre console, and under the bonnet at the base of the windscreen, under a cover or a panel there; on some vehicles it is somewhere else. Some vehicles have more than one cabin air filter, in one place or in several, for example where a further ventilation or air conditioning unit, such as one in the roof, has a filter of its own, and a few have none. Use the vehicle manufacturer's information to find every one your vehicle has.
• Find out what has to come off for access. On some vehicles a small flap or cover is all there is; on others the glove box, a trim panel under the dashboard, a cover in the engine bay or the panel at the base of the windscreen has to be removed, in some cases together with the wiper arms, and the job is considerably longer. Some wiper arms come off their spindles only with a puller: if the vehicle manufacturer's procedure calls for a tool you do not have, leave that work to a workshop.
• Where the filter is reached from the engine bay, let the engine cool first, and make sure that the bonnet's stay or struts hold it securely before you work under it. Keep clear of the windscreen wipers and their linkage, which can move if the ignition is switched on. An electric cooling fan can start by itself even with the ignition off: keep hands and tools clear of it. On a hybrid or electric vehicle, do not touch the orange high-voltage cables or the components they connect.
• Have the new filter ready before you start, and obtain the vehicle manufacturer's procedure and any tightening specifications it gives for the parts removed for access.
• Old filters hold dust, pollen and, in some cases, mould. Wear gloves and a dust mask when you handle one, especially if you have an allergy or asthma, and keep the old filter away from your face.
• Where the filter is reached from outside the vehicle, work in a dry place out of wind and rain, so that no water or dirt gets into the open housing.

Choose the right filter

Cabin air filters differ in shape and size, and many are made for one housing only. A filter of nearly the right size can leave a gap through which unfiltered air passes, be crushed out of shape or keep the housing from closing: fit only a filter listed for your vehicle and its equipment.

Select your vehicle with the selector on this page to see the part numbers listed for it. The vehicle's page shows part numbers with the specifications their suppliers state, such as the filter type and the dimensions; where a vehicle's list is long, it shows them for part of the part numbers only.

• Suppliers in the catalogue state a filter type for most cabin air filters. A particulate filter, which some suppliers call a pollen filter, holds back particles such as dust, soot and pollen. An activated carbon filter, which some suppliers call a charcoal filter, has in addition a layer of activated carbon, which can also hold back some gases and odours. Where both types are listed for your vehicle and no stated condition separates them, the choice is yours.
• For some part numbers the supplier states further properties, such as an anti-allergic effect or an antibacterial or fungicidal action. These are the supplier's statements about its product; we do not test them.
• Some vehicles take more than one filter, or a filter made of more than one piece. For some part numbers the supplier states that the part is a filter set, how many filters it contains or the quantity the vehicle requires. Find out from the listing and from the vehicle manufacturer's information how many your vehicle has, and replace all of them together, unless the vehicle manufacturer's schedule treats them separately.
• Where a supplier states conditions for a part number, such as left-hand or right-hand drive, with or without air conditioning, or a production period, they say which vehicles it is for. Where more than one filter is listed for a vehicle, they can be equivalent parts from different suppliers, different filter types or parts for different versions of the vehicle. If what is stated does not settle it, ask the supplier or the vehicle manufacturer before you buy.

All cabin air filter OE numbers in the catalogue

Remove the old filter

1. Before you remove anything, switch off the ignition and make sure that the blower cannot run, as described under Before you start. Where the filter is reached from the engine bay, let the engine cool if it has run and make sure that the bonnet is held open securely.
2. Remove what blocks access to the filter housing, as the vehicle manufacturer describes. Release a glove box, a trim panel or a cover only at the catches, stops and fixings it has, and support it while you do so; old plastic can be brittle, so do not lever it or force it. If a lamp, a switch or another electrical part sits in a panel that has to come away, unplug its connector only with the ignition off and after any electrical isolation the vehicle manufacturer's procedure requires, since switching off the ignition does not isolate every circuit: release any clip or lock on it and pull on the connector, never on the wires. Do not unplug any connector of the airbag system. Keep the fixings in order, and note where each belongs.
3. Where the filter sits under the bonnet at the base of the windscreen, clear leaves and loose dirt from around the cover before you open it, so that nothing falls in. Where a rubber seal or a strip has to be lifted or taken off to free the cover, note how it sits.
4. Open the filter housing as the vehicle manufacturer describes. Its cover can be held by clips, by a sliding catch, by screws or by a combination of these, and some covers are hinged or hooked in along one edge. Undo screws without dropping them, and find out which way the cover has to move to come free.
5. Before you take the filter out, note how it sits: which way round it lies, which face is towards the incoming air and, where the filter or the housing carries an arrow or a mark for the air flow or the fitting position, where it points. Note as well any frame, holder or cassette in which the filter sits and, where there is more than one filter or piece, the place and the order of each.
6. Take the filter out the way its mounting requires. Many filters slide out of a slot; some come out with a frame or a cassette from which they are then taken; some are held by tabs or clips of their own, which have to be released first, if the filter has any. Where the slot is narrower than the filter, the filter has to be flexed to come out, as the vehicle manufacturer describes. Draw it out slowly and keep it level, with its dirty face upwards where the position allows, so that the dirt it holds does not fall into the housing.
7. Look at the old filter's condition as you take it out, without shaking it or bringing it near your face: note whether it is wet, mouldy, damaged or heavily clogged. Then put it straight into a bag and close the bag. Do not knock the filter out, and do not carry it open through the passenger compartment.

On many vehicles the blower sits directly below or behind the filter. Nothing may fall into the open housing: a leaf, a screw or a clip that reaches the blower can jam it, damage it or make it noisy. If something has fallen in and you cannot see and retrieve it completely, do not switch the blower on, and have it removed by a workshop.

Clean and inspect the housing

1. Look into the housing with a lamp. Vacuum out the leaves, dust and other dirt you can reach, without pushing the nozzle or anything else into the blower or onto the fins of a heat exchanger behind the filter, if one is in reach. Then wipe the surfaces on which the filter and the cover rest with a clean, slightly damp cloth, and let them dry before the new filter goes in. Do not blow the housing out with compressed air, which drives the dirt further into the system, and do not use water, solvents or sprays in it unless the vehicle manufacturer's procedure expressly provides for them.
2. Check the housing and its cover for cracks and for broken clips, tabs or hinges. Where the cover or the housing has a seal of its own, check that it is undamaged and correctly seated, and replace one that is damaged. A cover that does not close evenly all round lets unfiltered air, and on some vehicles water, past the filter, and has to be repaired or replaced.
3. If the old filter was wet, or the housing is wet or shows water marks, find out where the water came from, for example blocked water drains at the base of the windscreen, a damaged or badly seated cover or seal, or a blocked condensate drain of the air conditioning, and have the cause put right: a new filter that becomes wet does not work properly, can grow mould and can freeze in winter.
4. Where the filter is reached from the base of the windscreen, clear the leaves and dirt from the area around the air intake that you can reach, and check that the water drains you can see there are not blocked.

A musty smell that remains with a new filter usually comes from further inside the system, often from the air conditioning's evaporator. Cleaning or disinfecting the evaporator and the air ducts is separate work with products and procedures of its own; follow the vehicle manufacturer's instructions for it or leave it to a workshop. Do not spray cleaners or fragrances onto the filter or into the housing unless the product is made for that use and the vehicle manufacturer allows it.

Fit the new filter

1. Check that the new filter is one listed for your vehicle. Then compare it with the old filter: shape, length, width and height, the number of pieces, the position of any seal, tabs or cut-outs, and the filter type. Where they differ in more than the filter type, do not fit the filter until its supplier or the vehicle manufacturer confirms that it is the right part. The filter that was fitted may itself have been the wrong one.
2. Check that the new filter is clean, dry and undamaged, with its pleats even and its frame or edge complete. Do not fit a filter that is damaged, dirty or has been wet. Take it out of its packaging only when you are ready to fit it, and remove all the packaging: a filter fitted in its film lets no air through.
3. Find the mark for the fitting direction on the new filter. Many filters carry an arrow for the direction of the air flow, and some are marked with the side that faces up or with the fitting position instead; the instructions supplied with the filter say what its mark means. The air flows from the air intake through the filter towards the blower or the passenger compartment, and on many housings an arrow shows this direction. If the old filter may have been fitted wrongly, go by the marks and the vehicle manufacturer's instructions, not by the old filter. Where neither the filter nor the housing carries a mark and the instructions do not settle it, ask the supplier or the vehicle manufacturer.
4. Make sure that nothing is left in the housing: no tool, cloth, fixing or piece of the old filter.
5. Insert the filter the way its mounting requires. A filter that sits in a frame, a holder or a cassette is first fitted into that part, the right way round and with every tab engaged, if it has any. Where the slot is narrower than the filter, flex the filter only as the vehicle manufacturer or the filter's instructions describe, without creasing its pleats or tearing its edge, and make sure that it has returned to its full shape inside the housing. Where there is more than one filter or piece, fit each in its own place and in the order the vehicle manufacturer describes, and join pieces that hook or clip together, if they are made to.
6. Check the seating before you close the housing, as far as the design lets you see it. The filter must have the shape it is made to have in the housing and sit fully home in its guides or on its seat, with its edge or seal against the housing all the way round, not folded or caught anywhere, and with no gap beside it. Fasten again any tab or clip that holds it, if it has any.
7. Refit the cover the way the vehicle manufacturer describes. Where it has hooks or a hinge, engage them first, and check that its seal, if it has one, is in place. Fasten every clip or catch, and tighten screws evenly and only lightly, to the vehicle manufacturer's tightening specification where it gives one: the threads are often in plastic. If the cover will not close evenly, do not force it: open it and look for a filter that is not fully home or is the wrong way round.
8. Refit everything that was removed for access as the vehicle manufacturer describes, in the reverse order, with new clips or fasteners where the manufacturer requires them, tightened to the manufacturer's values where it gives any. Plug in every electrical connector you unplugged until its catch engages, and fasten again any separate lock you released on it. Where electrical isolation was required, restore the electrical supply as the vehicle manufacturer describes before you switch on the ignition. Seat any rubber seal or strip at the base of the windscreen as it was. Where wiper arms were removed, refit them, each on its own side, in the position and by the procedure the vehicle manufacturer gives. Check that a glove box or a panel is held at every fixing and opens and closes as before.

Check the ventilation

1. Check that no tool, cloth, fixing or bag is left in the footwell, in the glove box or in the engine bay, and that nothing lies on the windscreen or in the path of the wipers. Close the bonnet if it was open.
2. Switch on the ignition and run the blower through the settings it has. Check it with fresh air and, where the vehicle has a recirculation setting and its controls allow it, with recirculated air. If the blower on your vehicle runs only with the engine running, first make sure that the vehicle stands in the open air and cannot move, with the parking brake applied and the transmission in neutral or in park; never run an engine in a garage or another closed space, because exhaust fumes are poisonous.
3. With the blower running, air should come out of the vents that the controls select. Where the blower speed can be set by hand, leave the air distribution unchanged and check that the air flow grows as you raise the speed. Listen for rattling, scraping or whistling that was not there before: it can mean that something has reached the blower, that the filter is not seated or that the cover is not closed. If you hear any, switch the blower and the ignition off, and check the filter and the cover again. Have the blower checked by a workshop if the noise remains.
4. If hardly any air comes out, switch off and check that all the packaging has been removed from the filter, that the filter is the right way round and that it has not folded over in the housing.
5. Where wiper arms or the panel at the base of the windscreen were removed, check with the windscreen wet that the wipers sweep their full area, park in their usual position and touch nothing.
6. Where the vehicle has a service indicator that has to be reset after the change, reset it as the handbook or the vehicle manufacturer describes. Record the filter change in the service record, whether or not an indicator had to be reset.
7. Dispose of the old filter, in its closed bag, as your local waste rules require.

Mistakes to avoid

• Fitting the filter the wrong way round, against the mark for the air flow or the fitting position
• Leaving the packaging film on the new filter
• Creasing or folding the filter to get it in, where the procedure does not call for flexing it, or leaving it folded over in the housing
• Letting leaves, dirt or a fixing fall into the blower
• Shaking out the old filter in or near the vehicle
• Leaving one piece of a filter made of several unchanged, or replacing only some of the filters that the vehicle manufacturer's schedule changes together
• Leaving the cover open, loose or with its seal out of place
• Forcing a glove box, a trim panel or a clip, or pulling on wiring behind them
• Unplugging or straining a connector of the airbag system
• Fitting a filter that is not listed for the vehicle because it is nearly the right size
• Spraying cleaners or fragrances onto the filter