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Technical Reference
FAQs - Lube Filtration

Q: Can the filter cause low oil pressure? Q: What is the purpose of a by-pass lube
While some pressure drop across the filter is normal, filter?
the oil filter is not capable of regulating the lube system A by-pass lube filter is used to continually filter the oil in a
pressure. Low oil pressure is generally the result of another system at a higher efficiency to remove contaminant that
malfunction in the engine such as the oil pump losing its is not efficiently removed by the full-flow filter.
prime or the pressure-regulating valve not functioning
properly. Reference FMC TSB 83-2R2 Q: What is the micron rating and efficiency
Q: What causes a gasket to displace from of the filter?
the oil filter? The micron rating of a filter represents the size of particle
that the filter can remove from the fluid passing through
Gasket displacement is the result of insufficient gasket it. The micron rating should be associated with an
compression during installation, excessive lube system efficiency or beta value to indicate how efficient the filter
pressure or a combination of the two. Any deformation to is at removing that size of particle. Any given filter will
the filter, from which the gasket was displaced, is a clear remove various sizes of particles. The difference between
indicator that the filter was exposed to excessive lube filters is how efficient they are at removing certain sizes of
system pressure. Excessive lube system pressure is most particles.
likely the result of a malfunctioning pressure regulating
valve that is failing to open properly. Reference FMC TSB 99-1R2 Q: What type of media does the filter use?

Q: Is it better to use a filter with higher There are many different types of media that can be used
efficiency, regardless of the capacity of the in lube filters. Earlier filters used a depth type media, that
type of media is still used in some filters today. Most lube
filter? filters now use pleated cellulose or cellulose blended
The correct filter for an application will have a good balance media. Some lube filters in specialized applications use
between efficiency and capacity for the application that it is synthetic media (glass) or glass-blended media.
used in. Using a filter with very high efficiency may lower
the dirt holding capacity of the filter enough to shorten the Q: What are the advantages of glass media?
life of the filter on the application, increasing the risk of the Glass media has more uniformity in the size of the
system going into by-pass. opening in the media, which can provide for better flow
performance. Glass media also has more dirt holding
Q: Can some filters be substituted for other capacity per square inch of media than most cellulose
filters? media blends.
This question is presented when customers are trying to ENGINE LIQUID FILTRATION - TECHNICAL REFERENCE
consolidate some of the filters that they carry. The filter
manufactures will not approve of such consolidation. While Q: What is the service interval of the filter?
there are some filters that may work in the place of others, After-market filter manufacturers design their filters to
filter manufacturers recommend against consolidation, meet or exceed the performance requirements of the
because each filter is designed after a specific OEM filter. original equipment manufacturer, for which the filter is
Additionally, if changes are made to a specific filter to keep applied. Therefore, the use of an after-market filter will not
it up to date with the OEM filter that it replaces, it may no affect the service interval recommendations of the original
longer be an acceptable substitute for another filter that it equipment manufacturer.
could be used in place of, previously.

Q: What is the difference between a by-pass
lube filter and a full-flow lube filter?
The oil that goes through the full-flow lube filter goes on to
lubricate the engine. The by-pass lube filter receives about
10% of the amount of oil that flows through the full-flow
filters and filters that oil at a much higher efficiency. The oil
that flows through the by-pass lube filter then returns to the
sump. Due to the high efficiency of the by-pass lube filter,
it cannot handle the same volume of flow as the full-flow
filter. A metering orifice is commonly used to meter the flow
of oil through the by-pass filter.

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