Internal combustion engines consume vast quantities of air and in order to remove the harmful abrasive particles which are drawn fro the surrounding atmosphere a relatively large area of filtering medium is required .

When an air filter starts to block, the air flow through it becomes restricted, causing the air/fuel ratio to change giving a richer mixture and results in un-burnt fuel leaving the engine as black exhaust smoke. When this occurs it is advisable
to check the condition of your air filter element and replace it if necessary. The un-burnt fuel wastes money, washes oil from the cylinder bores accelerating engine wear, can cause loss of power and its emission is illegal in many countries.

If a vehicle is used without an air filter, harmful abrasive particles will enter the engine through the induction system, coming into contact with the inlet valves, most leaving via the exhaust valves, but some remaining in contact with the pistons and bores and causing accelerated wear to the piston rings and cylinder liners, eventually reaching the crankcase and contaminating the lubrication system.