How to replace and upgrade your MG ZR / Rover 25 K series panel air filter to a performance K&N filter.

Rover 25 MG ZR performance air filter choices
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Time to Complete - 5-15 minutes


Difficulty - 1/5


Tools and Parts Required

  • Replacement air filter
    • Performance (recommended) or
    • OEM type
  • Performance air filter cleaning kit
    • If you've fitted a performance air filter from brands such as K&N or Pipercross, instead of replacing it you can just clean it instead. I've link to a couple of recommended kits below! (Step 4 and 5)



Disclaimer: Any information given in this guide is to be used at the readers own risk. I take no responsibility for injuries to the reader or damage to their vehicles. If this guide is followed correctly, no harm should occur to either the reader or the car.

Please read through the entirety of this guide prior to undertaking any work, and take due care.


How to Replace and Upgrade Your Rover 25 / MG ZR Air Filter



Step 1 - Locate the Air Filter Housing

You will need to locate the air filter housing, it is situated to the right of the engine (looking from the front of the car at the engine bay) and to the left of the battery. It looks as shown below.

Rover 25 MG ZR K series air filter housing

Step 2 - Release the Air Filter Housing Clips

There are four clips holding the top half of the air box to the bottom. Two of the clips push down, and two push up. The two at the rear push down, and the two at the front (nearest you) push up. Unclip all four to proceed.

Rover 25 MG ZR K series air filter housing upper to lower clip

Rover 25 MG ZR K series air filter housing upper to lower clip



Step 3 - Removing the Top Half of the Air Box and Air Filter

Once the four clips have been unclipped, the top of the air box should come away from the bottom quite easily. This will reveal the existing air filter to you, to remove the air filter, simply pull it out.

Standard paper Rover 25 MG ZR K series panel air filter

Step 4 - Choosing an Air Filter

If you have a standard type paper air filter, as shown in step 3, you will need to remove, dispose of it and fit a replacement (only if it is soiled and in need of replacement though).

Rover 25 MG ZR performance air filter K&N 33-2762
I'd definitely recommend you fit a performance air filter instead though. I fitted a K&N performance air filter to my Rover 25 and was surprised with the difference, it added a throaty induction sound, a marginal improvement to throttle response and made the 1.4 K series rev slightly more freely.

Click the links below to go the K&N Amazon store and pick one up for your next service!


If you're not a fan of K&N, there are other options:

Let me know in the comments below which one you chose and why? Would you recommend it?


Step 5 - Cleaning Your Performance Air Filter

To clean your performance air filter, most manufacturers recommend using their own cleaning kit. I used K&N's Air Filter Recharger Kit which worked a treat come annual service time. It's simple enough to use and doesn't take long at all.




Step 6 - Clean Your Air Box

Whilst the air filter is out of the air box, it's worth vacuuming out any dirt in the bottom of the air box, you don't want to get your new air filter dirty straight away and you definitely don't want any debris getting into the engine.

Without the air filter, the air box looks like this. Your's may look slightly different, I've removed the restricting air box pipe, this is a common modification to improve induction sound and air flow.

Rover 25 MG ZR K series air filter housing with plastic cone removed



Step 7 - Fit Your New Air Filter

Place the new or cleaned air filter back into the bottom of the air box, making sure it's seated down properly. Then just re position the top of the air box onto the bottom and do up all the clips.

Rover 25 MG ZR K&N performance air filter for 1.4 105 1.6 120 and 1.8 160

Job done!

Don't forget to let me know in the comments below which one you chose and why? Would you recommend it?