K&N Filter Change


Registered User
The long life service intervals of 30,000 miles are way to long for a paper element so

I fitted a K&N filter when the car only had approx 7000 miles on the clock and now it has reach 55,000 I decided to give it a clean. This guide is for all filter replacement regardless of filter fitted.
You will need:
K&N or Green Cotton filter cleaner and oil
Axle stands
T25 bit TORX
Cross head screw driver & 6mm spanner
10mm socket on long extension bar
1. Jack up car and place securely on stands
2. Remove undertray using T25 torx at all fixings. (see audi pic)


3. The location of the airbox is just inside the bumper next to the offside/drivers side wheel. it looks easier to get to in the Audi pic than it is

4. It is held in by 2 screws and a small retaining lip. Undo the accessible screw with the cross head screw driver and the other with a 6mm spanner.


5. Now you will have access to the filter and with a little bit of flex on the bumper plastic, you can remove the filter from the housing straight down with a simply pull.


6. Clean the housing with either a damp cloth or suitable paper. Fit a new paper filter at this point and reverse the procedure above to fit and complete the process. Ensure you clip the base plate in correctly and securely before you re-do the retaining screws.

7. K&N cleaning: I got the cleaner and re-oil fluid with a brush and a basin so I could literally bath the filter in the cleaning fluid.

8. Apply the cleaner and brush on to the seams of the filter. Leave for 20 mins and finish your cup of tea.
9. You can see the dirt and old oil coming out of the filter. BTW the filter cleaner is clear so you can see the level of dirt!

10. Wash the filter from the inside out using warm water (I did this in the sink so I had warm water under pressure)
11. Having cleaned it I decided to reapply the cleaner and do the process again to ensure it was clean, (it states you can do this if the filter is dirty) as you can see the second pass produced only clean filter cleaner back through the filter indicating that I probably didn’t need to do this. But its up to you.

12. I left it a further 15mins and washed it through with warm water again.
13. Remove excess water (as you do with a paint brush or something) and allow to dry naturally for 30 mins

14. The tricky bit, how much is too much filter oil? Ensure the filter is dry and apply the spray on oil, too little and the cotton gauze won’t filter enough particles. Apply to much and it can effect air flow Meters. The air flow meter argument is not that likely on the A2 I think, simply due to the speed and volume of air inducted into the little engine, and the location and distance from the air flow meter. However do not over do it.

15. Allow the oil to soak into the filter for 20 mins and clean excess oil off the rubber ends. (you can refit at this point without waiting 20mins if you aren’t driving the car straight away)
16. Simple refit and you are done!! Put a smll bit of grease on the screws and wipe the inside of the base plate


Remove the fog light blanking plate from the off side, and you will see a perfect flat side to the Air filter box. Obtain an offside fog light plate, drill a suitable size hole in the air box. Using duct hose and a top hat adaptor to the air box with silicone sealant. This will provide increased air flow to the air box.


Black Flexi hose: http://www.green-filter.co.uk/index.php?cPath=696_662
Top Hat adaptor: http://www.green-filter.co.uk/index.php?cPath=634&osCsid=086b33d216603ee32376031da4b683e1

I haven’t tried this but someone must have!!