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Technical
Service Bulletin 99-1R2
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Gasket Displacement
The
information in this bulletin corresponds with the TSB
83-1R2 bulletin regarding over-pressurized lubrication oil filters
and TSB 94-4R1 regarding compression gaskets.
As stated in TSB 83-1R2, deformed filters are
the direct result of excessive lubricating system pressure. Excessive
lubricating pressure is the result of a stuck or otherwise malfunctioning
pressure regulating valve in the oil pump assembly and should not be attributed
to a fault with the filter. This bulletin addresses situations that involve
gasket displacement between the filter and the filter mounting base on
the engine, when no physical evidence of filter deformation due to excessive
internal oil pressure is evident.
Gaskets displace from filters due to excessive lubrication system pressure, insufficient gasket compression or a combination of both. Gaskets that are displaced from filters may have witness marks in the areas where the displaced gasket was trapped between the base of the filter and the mounting base. These witness marks may be found on any surface of the gasket, but are generally found on the inner wall of the gasket. The illustrations below give an example of how these witness marks may appear on a used gasket.
Generally,
the filter will be permanently deformed prior to the displacement of a
properly compressed gasket. Such deformation can be seen in the canister,
seam or baseplate of the filter. Since most filters will withstand a minimum
of 100 - 150 psi without deformation, a deformed filter is a definite
indicator of excessive pressure in the lubrication system. However, there
are occasions when filter manufacturers receive reports of displaced gaskets
on filters that have no permanent deformation.
In
these instances, the gasket may have displaced from the filter at a pressure
significantly less than 200 psi. The most probable cause of this situation
is a slow operating or malfunctioning pressure regulating valve in conjunction
with a gasket that was insufficiently compressed to the sealing surface
of the base.
The
lubrication filter is a passive component of the lubrication system. It
is neither designed nor constructed with the capability of either increasing
or decreasing the lubrication system pressure. As a passive component,
the filter is subject to the pressure developed and regulated by the oil
pump and its pressure regulating valve. TSB 83-1R2
explains this issue in more detail. In the event that a gasket is displaced
from a filter due to excessive lubrication system pressure, the equipment
owner should have the oil pump and pressure regulating valve, which is
usually a component of the oil pump assembly, serviced or replaced to
avoid future failures.
Most
filter manufacturers recommend tightening their filters two-thirds to
one full rotation after the gasket contacts the base to achieve adequate
gasket compression on automotive applications. Filters for heavy duty
applications may require up to one and on-half rotations to properly compress
the gaskets. In most cases, the proper installation instructions can be
found on the filter or packaging. It is important that the proper installation
instructions be followed for each filter to avoid premature filter failure.
Test data shows that the gasket can be displaced from the filter at pressures
much lower than required to permanently deform the filter if the gasket
is not sufficiently compressed.
The
proper installation instructions must be followed closely for each filter
application to insure gasket displacement will not occur during operation
with normal internal oil pressure ranges or surges. Other practices that
will help protect against leaks from the filter include; pre-lubricating
the gasket with the recommended fluid, cleaning the sealing surface of
the filter mounting base on the engine and assuring the gasket is properly
positioned in or on the filter.
For additional information, contact:
Filter Manufacturers
Council
P.O. Box 13966
Research Triangle Park, NC 27709-3966
Phone: 919/406-8817 Fax: 919/406-1306
www.filtercouncil.org
Administered by Motor & Equipment
Manufacturers Association
Revised October 2004
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