Filter Cleaning

“With what should I clean my filter?”

            The preferred product for cleaning is mineral turpentine (“turps”).  It is the only safe solvent for use in cleaning polyurethane foam.  All other solvents will have some detrimental effect on the foam structure over a period of time.


            As an alternative, Unifilter’s “Foam Filter Cleaner” solution is a detergent-based wash designed to be used where mineral turps is either unavailable or inconvenient to use.  As turps is a solvent it should not be carried within a vehicle.  “Foam Filter Cleaner” is designed therefore for use when the customer needs to carry out air filter servicing enroute.


“Can I use petrol, gasoline, kerosene, diesel fuel, methylated spirits etc to clean my filter?”

            All of these products will have some greater or lesser detrimental effect on the polyurethane foam over time and therefore should not be used.


“Should I wash out the foam with soap and water after cleaning with mineral turps?”

            No! – this action is completely unnecessary.  After cleaning with mineral turps pad the foam dry with an absorbent cloth.  Any further residue will evaporate within minutes.  Should the foam be immersed in water, then if every trace of moisture is not removed prior to re-oiling it will be trapped within the foam by the oil and cause long-term damage to the foam’s structure. 


Filter Oiling


“Can I use any oil to re-oil my Unifilter?”

            No! - The best oil for foam air filters is a mineral-based oil.  Unlike synthetic oil, mineral-based oil will never dry out.  A synthetic oil may be good for inside an engine, but when used on a filter in dusty conditions the oil will dry when it comes into contact with dust.  Once the dust comes into contact with a synthetic-based foam filter oil, a dry crust will form on the surface of the filter allowing more dust to pass through the filter and into the engine.  Unlike a synthetic-based oil however, a mineral-based oil will soak through the dust and continue to catch new dust thus protecting the engine.


Unifilter’s “Filter Fix” oil has been specially formulated for this sole purpose.  It has a balanced consistency which allows the oil to penetrate the entire foam yet not “drain” from the foam whilst in situ.  In addition, it contains special “tackifier” agents to enhance the dust holding characteristics of the oil.


“Are there any other filter oil brands I can use?”

            Yes! – Unifilter recommends the use of either Castrol or Belray brand filter oil where “Filter Fix” is unavailable.


“Can I use K&N’s cotton grid air filter treatment on my Unifilter?

            No! – the K&N and Unifilter product characteristics are incompatible.


“Can I use a spray-on oil treatment for my Unifilter?”

            These are not recommended.  Whilst spray-on treatments may be easy and convenient to apply, the propellants used to make the product spray-able will shorten the life of the foam.


“What is the best way to evenly distribute oil throughout the filter?”

            When possible, always warm “Filter Fix” before use.  The best way to do this is to stand the “Filter Fix” bottle in warm/hot water as you would with a baby’s bottle.  This effectively reduces the oil's viscosity and makes it easier for it to saturate the foam.


            Pour a quantity of oil into a suitable container (a used ice cream container is ideal) and work oil through to thoroughly saturate the foam.  As a less messy alternative, place oil and foam into a seal-able “zip-loc” bag.  Manipulate the bag to ensure oil is worked well through the foam.  Snip a bottom corner from the bag and squeeze leftover oil back into its bottle for future use.


            Fold and squeeze the foam to remove any residual oil.  It is recommended to then wrap the foam in an absorbent cloth a squeeze again.  You can never remove too much oil using this method.  The correct amount of oil in the foam is when pinching by hand will “just” produce a small amount of residual oil on your fingers.