My car was due for her fourth service soon, so I decide to do a little pre-service of my own.
I had replaced the stock air filter with a better aftermarket replacement filter. This new filter is better as they are washable and reusable, as opposed to the single-use stock filter that you completely replace on every other service, or 10000 km. Although the aftermarket filter is pricey, in the long run it will pay back for itself.
Other than that, the aftermarket air filter (in this case, a stock-replacement drop-in filter) has a much higher rate of airflow while retaining, if not better, filtration capabilities. My experience in using them is slightly better fuel economy and better acceleration as the engine breathes easier. After all, it's easier to breathe through a cotton cloth (aftermarket filters) than a piece of carboard (OEM filters).
Even so, I do not imply that the stock filters were not good - it gets the job done. Good, pricey aftermarket parts does the same job as stock parts too, only better.
Medusa is equipped with a hi-flow K&N filter. This filter is made from thick cotton sandwiched between wire mesh. This type of filter is oiled to provide the best filtration capability, and it's different from foam-type aftermarket filters.
I clean mine every 10000 km or so, but if you drive on dusty roads alot, clean them more frequently.
This filter could be serviced at the place you bought the filter, or you could buy this cleaning kit for DIY Car Care. The multi-tool above is used to undo the securing screw of the airbox.
This kit is by K&N, and it comes with a bottle of Air Filter Cleaner, and a bottle of Air Filter Oil. The other version of this kit comes with a bigger bottle of the Air Filter Cleaner with a trigger-spray, and an aerosol can of the Air Filter Oil.
First off, undo the latches securing the airbox.
Three latches in total for the Neo. Plus one screw at the south point.
Just one simple screw. You don't have to unsrew it all the way.
Remove the filter, and visually inspect it for any damage. The filter will have a dirty side where it comes in contact with outside particles. Identify which side it is on - usually it's the side with small bugs are trapped in-between the pleats, or dustier pleats. Shake the debris loose, and (lightly) tap the filter to dislodge the debris.
Flip the filter so that the dirty side is facing downwards. Spray the filter with theAir Filter Cleaner until it's soaked with the cleaning solution.
Let the filter sit for 10 minutes to ensure that the cleaning solution soaks and seeps into the pleats thoroghly. The stock filter that my K&N filter replaces is for comparison.
Notice the higher number of pleats on this filter. The other major difference is that this filter is 'dry', in contrast to my K&N aftermarket filter which is oiled for best filtration capability.
This filter is made of cardboard, or thick paper that is very restrictive for the airflow. Like I said, using the stock filter for your engine is like putting a tight cardboard box against your face and trying to breathe through it.
Rinse the filter thoroughly. DO NOT use high pressure water, or a high pressure air blower. It will damage the pleats and shortens the filter's lifespan. Use a normal garden hose or tap.
It's also important to rinse the filter by passing water from the cleaner side. If you rinse with the 'dirty' side on top, you might push some smaller contaminants deeper inside the filter.
Set the filter out to dry. Ensure that the filter is dried thoroughly, and drying it out under the sun is a great way. Else, dry the filter on some newspapers overnight, preferably in a room with the fan on.
When the filter is completely dry, notice the change of color.
The filter is ready for the next step - re-oiling
Follow the instructions carefully - particularly about the amount of oil needed to re-oil the air filter. If you over oiled the filter, it might mess up the MAF (Mass Air-Flow) sensor,a nd other engine components.
The correct amount of oil to be used for the filter is indicated on the bar code label of the airfilter's box.
The air filter oil bottle has a scaled measure with a see-through window. Use it.
On the 'dirty' side, draw a bead of the oil across the top of the pleat. Use a consistent amount on each, and use only a single, continuous pass.
When all the pleats were oiled, set it aside for about 20 minutes to let the oil wick through the pleats completely. If you do it right, turning the filter over will reveal that the other side of the filter - the 'clean' side - evenly coated too. Dab some more oil on any spots missed.
Before installing the air filter back to the airbox, clean the box and inspect for any large debris or damages.
Finally, re-install the air filter, with the 'clean' side facing to the intake manifold, back to the airbox. Ensure the sides are properly inserted to make a good air seal.
Latch the closures shut, and screw it home. Now your air filter is good to go!