There are conflicting views about the improvements obtained by replacing your car’s air filters to K&N Stock Replacement Drop-In Air Filters, with claims that due to the larger pores allowing more air into the engine for increased performance, it also allows in more dirt, potentially causing engine wear.
Personally, I think these washable cotton-pleat filters are ok, provided that they are cleaned periodically or when necessary using the right methods, and more importantly that they are oiled as per manufacturer’s instruction.
No matter how “large” the pores are supposedly claimed to be, I believe they are still not large enough to allow dirt big and coarse enough to cause engine wear. Anything too small that can possibly get past the pores is probably too fine to cause damage and not very different in size from those that are let in through stock paper or synthetic air filters.
The oil layer on the air filter acts as a tacking agent to capture these minute particles. You would do more damage by not replacing your engine oil following the recommended frequency regardless of the type of filter used. However, we will save this argument for another day.
Today, I’m going to show how I replaced the standard stock air filter in the Alfa Romeo 147 with a suitable washable cotton-type drop-in air filter by K&N – Part No.33-2218. You can get the correct Part No. for your car make and model on the K&N website, or click here to begin your search on Amazon – be absolutely sure to select the right K&N air filter based on your car model!