Abstract: A lubricating oil filter and filter blockage alarm system for internal combustion engines. At least one filter element is disposed within a housing. A condition representing a degree of blockage of the filter element is sensed and, if a blockage threshold is exceeded, an alarm is triggered. There is provided an electrical connection between the sensor and the alarm system. The connection is a pair of series-connected platinum conductors that are insulated from contact with the oil being filtered, thereby assuring the triggering of the alarm.