COVER STORY: Oil Filter 101

WHEN TO CHANGE OIL FILTERS

Oil filters should always be changed with the motor oil. Intervals in the owners’ manual should be adhered to. Always check the owner’s manual to determine when fluids and filters should be replaced. It is very important to note that there are different recommended change intervals depending on the type of driving that consumers do. Most fall into the “severe service” category, but don’t realize it.

HOW DOES THE OIL FILTER WORK?

The vast majority of oil filters used in automobiles today are full flow filters. With this type of system, all of the oil is filtered before it passes into the engine. Full flow filters must provide low restriction to the oil flow while having a high degree of single-pass efficiency.

The majority of automotive oil filters today use pleated filter media, which increases surface area for high filtration efficiency within a relatively small space. However, the number of pleats in the media does not have as much bearing on filtration as the quality of the media itself. With thicker, high quality media, the filter design may in fact call for fewer pleats to improve the fluid flow and filter performance.

OVER-PRESSURIZED FILTERS

Sometimes a used oil filter will appear bulged or deformed. A bulged oil filter is one that has been subjected to too much pressure — a condition that occurs when the oil pressure-regulating valve is malfunctioning. When a bulged oil filter is discovered, the pressure-regulating valve should be serviced immediately.