Element Replacement frequency is determined by the contamination level in fuels. Fuel flow to the engine becomes restricted as the element gradually plugs with contaminants, resulting in noticeable power loss and/or hard starting. When any one of these occur, change the element as soon as possible. As a guideline, change the element every 500 hours, 10,000 miles, every other oil change, annually or at the first indication of power loss, whichever comes first. Always carry extra replacement filters as one thankful of excessively contaminated fuel can plug a filter.