If the Viroclean air cleaners are fitted onto electronic diesel engine they must be serviced with water and washing powder every 300 hours, let it dry or use compressed air (Max 5 bar) to avoid to damage the filter element. If the Viroclean is used onto aspirated diesel engines they must be serviced every 200 hours. Every 2 / 3 years the air cleaner should be replaced ( type A ) or replace the sponge (type B ). Sometimes it is necessary replace also the air cleaner ( type B ) completely every 2 / 3 years.