SEAL-LIP TYPE 3278745 - Caterpillar

purpose of a filter element is to keep foreign material of any type out of the engine. Dirt, debris, or metal particles, in the clean side of the filter element can flow into the engine and cause high-cost damage. Foreign material in the element can come from several sources. Small metal particles from the time the threads were cut, or from other machine work, have been found in some spin-on filters. Dirt and debris from the outside can get into the filter element if the package is damaged. Be careful to keep dirt out of the filter element after it is removed from the package.
Because of the many possible sources of foreign material in filter elements, make a careful inspection to be sure the element is completely clean before it is installed. This will make sure the element gives maximum protection against possible engine damage.