The main purpose of an oil filter is to prevent large particles of dirt from causing damage to equipment components. In order to help control contamination within lubricated systems, follow these 12 guidelines for using oil filters:

 1. Always use full-flow oil filters that meet the original equipment manufacturer’s (OEM’s) specifications for pressure drop, flow rates, bypass valve cracking (opening) pressure and absolute micron rating.

 2. Always replace full-flow oil filter elements at (or before) the recommended change interval, particularly when working under extremely dusty conditions.

 3. Periodically use oil analysis to monitor diesel soot levels and hydraulic oil contamination levels.

 4. Install depth-type filters on all engines and hydraulic systems on a side stream or parallel circuit to control combustion soot, hydraulic system “silt” and water contamination. Depth-type absorbent filters of the finely wound paper type are particularly effective in removing water.

 5. Never use coarse filters in an attempt to obtain longer filter life. If contamination levels are high and it is necessary to change filters often, obtain and install larger filters of the same quality to increase dirt capacity.

 6. Expect short filter life initially when installing a depth-type filter in a parallel circuit. This is a common but temporary situation because the fine depth filter must first clean up the contamination, which the more coarse full-flow filters cannot remove.

 7. Never drain the oil without replacing the oil filter element. If a choice must be made between whether to drain the oil or replace the full-flow filters, replace the filters.

 8. Always use hydraulic reservoir breather filters as fine as the full-flow filter used on the system.

 9. Always use lubricating and hydraulic oils of the correct viscosity.

10. After a repair has been carried out, never re‑install used hydraulic oil without pre‑filtering the fluid and always flush a repaired system under “no load” and low pressure.

11. Never use “adsorbent” depth-type filters. These filters differ from “absorbent” depth-type filters in that they contain chemically active media, such as charcoal or fuller’s earth. The danger in using these filters is that while they remove contamination, they may also remove oil additives through a chemical reaction.

12. Never base the purchase of replacement oil filters on price alone. The old saying, “You get what you pay for,” is particularly true when buying filter replacements.