Servicing · Hackbridge, South London

Engine air filters changed when they need changing

An air filter is a small job that tells you a great deal, which is why it is worth having someone look properly rather than posting a new element through the airbox lid. The pattern of dirt on the old one says whether the seal has been doing its job. Leaves in the housing say the scuttle drains are blocked. An oily film says something else needs attention. Ours start from £35 at the Hackbridge workshop, fitted with an OE-equivalent element for your exact engine, and if the old one still has life in it we will tell you so instead.

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From £35 · 15–45 minutes
Mon–Sat 8am–8pm

Mercedes in for an oil and filter service at KITH Cars Garage & Bodyworks, Hackbridge

From £35Written quote before we start

15–45 minutesTypical time in the workshop

3 monthsWorkmanship warranty

17 areasCollection across South London

Refitted if still serviceable

A filter with life left in it goes back in and you are shown why. There is no sense replacing paper that is still doing its job.

Matched to your engine code

The same model often takes two or three different elements depending on the engine fitted. We check the code rather than the badge on the boot.

The whole intake looked at

While the box is open we check the ducting, the airflow sensor, the lid seal and the drains, which is where most air filter jobs actually turn something up.

Sensible to combine with a service

If the car is already booked in for a service or an MOT, the filter saves you a separate trip and the rest of the intake gets checked the same day.

In the workshop

How we handle air filter replacement at Hackbridge

The old element comes out and is looked at in daylight before the new one goes anywhere near the box. An evenly grey filter that has done its miles is straightforward. A clean streak running across otherwise dirty pleats means air has been getting round the seal rather than through the paper, which usually points to a warped lid, a missing clip or a filter that was never the right size. Damp pleats, or standing water in the bottom of the housing, generally lead back to a blocked scuttle drain or a split duct rather than to the filter itself.

With the box open we look at the rest of the intake. The concertina section of ducting between the airbox and the throttle body or turbo splits along its folds and is easy to miss with everything assembled. The mass airflow sensor sits in that ducting on most cars, so we check its element is clean and its sealing ring intact. Rodent damage deserves a mention because it is more common than owners expect on a car that has stood for a few months: nesting material in the housing, and chewed insulation on the loom running past it.

Fitting is the quick part, but the seal decides whether any of it mattered. The new element is seated all the way round and every clip is engaged, because a lid held by three clips out of four draws unfiltered air whenever the engine pulls hard. Which filter goes in is confirmed from the engine code rather than the model, since plenty of cars share a shell and take two or three different elements. And if the old filter is honestly still serviceable, it goes back in and we tell you why, rather than charging you for a part the car did not need yet.

Servicing

Air Filter Replacement: what’s involved

Every litre of fuel your engine burns needs thousands of litres of air, and the engine air filter stops the dust, grit and debris in that air from reaching the cylinders and turbocharger. It is a pleated paper or synthetic element in a sealed box, usually at the front of the engine bay. As it traps dirt it slowly becomes more restrictive, especially in dusty conditions or heavy traffic.

On modern fuel-injected engines, a dirty filter mostly costs you performance rather than fuel, as the engine management adjusts fuelling to the air it measures. The bigger risk is a damaged or badly seated filter, which lets fine dust past to wear the cylinders and turbo, and to contaminate the mass airflow sensor, which the engine relies on to measure air accurately.

Signs your air filter needs replacing

Visibly dirty filter

A filter that is grey or black across the pleats, or has leaves and debris in it, is due. A little discolouration on the intake side is normal.

Sluggish acceleration

A heavily restricted filter can reduce power, most noticeable when accelerating hard or climbing hills, because the engine can't draw in enough air.

Past the service interval

If the filter wasn't changed at the last full or major service, or the history doesn't show when it was done, it is worth replacing.

Mass airflow sensor faults

Dust getting past a damaged filter can contaminate the airflow sensor, causing hesitation, flat spots and fault codes.

Unusual intake noise

A whistling or sucking sound from the airbox can point to a poorly sealed filter, a split intake hose or a damaged airbox lid.

Signs of water or oil

A damp or oily filter suggests water getting into the intake or crankcase breather problems, which need checking rather than just a new filter.

When should it be done?

Most manufacturers specify a new air filter somewhere between 20,000 and 40,000 miles or every two to four years, and it is often part of a full or major service. Check your schedule, as intervals vary widely by engine. Cars driven on dusty roads, near building sites or in constant stop-start traffic may need it sooner. We inspect the filter at every service and will tell you honestly if it still has life left.

Typically every 20,000–40,000 miles, depending on the manufacturer
Often every 2–4 years on low-mileage cars
Sooner in dusty conditions or heavy urban traffic
Whenever the filter is damaged, wet or oily
At a full or major service where the schedule calls for it

How we replace an air filter

Check-inWe confirm the engine and the correct filter part number, as some models use different filters for different engine versions.
Open the airboxWe release the clips or screws on the airbox lid, removing covers or intake pipes first on engines where access is tighter.
Inspect the old filterWe look at the dirt pattern and check for oil, water or signs of dust bypassing the seal, which can point to other problems.
Clean the airboxWe remove leaves and debris from the airbox and check the housing and seals for cracks or distortion.
Fit the new filterThe new filter is fitted with its seal seated all the way round, and the lid and any pipes are secured correctly.
Check and hand overWe start the engine, check for fault codes if needed and confirm the intake is sealed, then show you the old filter.

Parts we fit

We fit OE-equivalent air filters from suppliers such as MANN, Mahle and Bosch, which supply filters to many vehicle manufacturers. These match the original for size, pleat area, seal design and filtration efficiency. Cheap filters with thin media or poor seals can let dust through, which is a false economy on turbocharged engines. We don't fit oiled performance filters as a routine replacement, as excess oil can contaminate airflow sensors.

OE-equivalent panel and cylindrical air filters
Filters from suppliers such as MANN, Mahle and Bosch
Correct filter for your specific engine version
Airbox seals or clips where damaged, quoted separately

How long it takes

15–45 minutes

On most cars the job takes 15–30 minutes. Some engines need covers or intake pipes removed first, which can take longer. You can usually wait, or have it done alongside a service.

What’s included

OE-equivalent air filter for your engine
Airbox cleaned of debris
Seal and housing inspection
Check for signs of oil or water in the intake
Old filter shown to you on request

Worth knowing

What people get wrong about air filter replacement

Blaming the filter for rough running

A blocked element costs you top-end power. It does not cause misfires, hesitation or a management light, so a new filter will not cure any of those.

Spraying cleaner into an open intake

Carburettor and throttle cleaners aimed down the ducting can reach the hot-wire element inside the airflow sensor and damage it. That part costs several times what the filter does.

Ordering by model rather than engine

Plenty of online listings match on model and year only. A filter a few millimetres out will go in and look right, but it will not seal, which leaves the engine worse off than the old one did.

Not looking after a car has stood

A vehicle left for a few months can gather nesting material in the airbox. It restricts airflow, and anything loose in the housing sits on the wrong side of the filter.

Instant quote

Price your air filter replacement now

Enter your reg and we’ll look up your car, then price the job from our own labour rates and the book time for your model. Nothing is booked until you say so, and the written quote comes before any work.

Free, about 30 seconds, no sign-up
Parts, labour and VAT included
3-month workmanship warranty
Collection and delivery across South London

“It’s rare to find a garage you can truly trust. Fair price, brilliant customer service.”Thinushan K. · ★★★★★ Google

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Questions

Air Filter Replacement: your questions answered

Can I book just an air filter, or does it have to be part of a service?

On its own is fine, and it starts from £35. If the car is due other work it usually makes sense to do both together, but we are happy to see a car in for one small job.

Can I supply my own filter for you to fit?

We will fit a part you have supplied, and we will say before we start if it looks like the wrong one for your engine. Our 3-month workmanship warranty then covers the fitting rather than the part, so if a poorly made element fails you would be paying the labour a second time.

Will having it done here affect my service record or my warranty?

No. Work carried out by an independent garage to the manufacturer's schedule, with parts of matching quality, keeps a manufacturer warranty intact under the Block Exemption rules. We record the part fitted and the mileage on your invoice so the history stands up later.

Can you do the cabin filter at the same visit?

Yes, and it is quoted as a separate item so you can see what each one costs. We check both and tell you which is actually due, rather than assuming they fall together.

Will a new air filter improve my fuel economy?

On older carburettor engines it could make a noticeable difference. On modern fuel-injected cars the engine management adjusts to the air it measures, so a new filter mainly restores lost performance, with little change to fuel use. We won't promise mpg gains we can't back up.

Is the air filter the same as the pollen filter?

No. The engine air filter cleans the air going into the engine. The cabin or pollen filter cleans the air coming through the vents into the car. They are separate parts with separate intervals.

Can an air filter be cleaned and reused?

Standard paper filters should be replaced, not cleaned. Blowing them out with compressed air can damage the media and let dust through. Only filters designed to be washable should be cleaned.

Can I just change it myself?

On many cars it is a simple job, but on others the airbox is buried under covers and pipes. If you do it yourself, make sure the seal is seated properly and the lid clips are fastened, as a poor seal defeats the point.

Do performance air filters help?

On a standard engine, gains are usually very small. Oiled cotton filters can shed oil onto the airflow sensor if over-oiled, and some filter less finely than a quality paper element. For a daily car we recommend the OE-equivalent filter.

Air Filter Replacement near you

We look after air filter replacement for drivers right across South London. Pick your area for local prices, directions and collection:

Beddington~6 min away Carshalton~5 min away Cheam~12 min away Coulsdon~17 min away Croydon~15 min away Mitcham~8 min away Morden~12 min away Norbury~18 min away Purley~15 min away Rosehill~9 min away Streatham~20 min away Sutton~10 min away Thornton Heath~15 min away Tooting~18 min away Wallington~6 min away Wimbledon~20 min away Worcester Park~20 min away

Related work we do

Car ServicingFrom £155 · 1–4 hoursInterim, full and major servicing for all makes, carried out to the manufacturer's schedule with the correct specification oil.Cabin Filter ReplacementFrom £35 · 15–60 minutesPollen and cabin air filter replacement for all makes, including activated carbon filters.Engine DiagnosticsFrom £122 · 1–2 hoursA proper diagnosis of warning lights, running faults and electrical problems, not just a code read.ECU RemappingFrom £220 · 2–4 hoursStage 1 and Stage 2 ECU remaps for turbocharged petrol and diesel engines, carried out after a health check so the car is fit for the extra power.MOT TestingFrom £50 · 45–60 minutesClass 4 MOT testing for cars and light vans at a flat £50, under the DVSA maximum fee of £54.85, with nothing added for booking or admin.Brake RepairsFrom £110 · 1–3 hoursBrake pad and disc replacement, calliper and slide pin servicing, brake fluid changes and hose and pipe repairs for all makes.