Oil properties diagnostic system for work machine

A diagnostic system for a work machine that collects pieces of information from the work machine and determines an abnormality of the work machine based on the pieces of information that are collected, the diagnostic system comprising:

• a data storage device in which at least one piece of sensor information input from at least one sensor that senses at least one oil property about oil used for operation of the work machine and a determination value defined as at least one determination value for each kind of the sensor information are stored;
• and
• an arithmetic processing device that executes first processing of discriminating a degree of abnormality level of the oil based on the at least one piece of sensor information and the determination value relating to the at least one piece of sensor information, second processing of determining whether or not necessity to carry out oil analysis involving oil extraction exists based on the degree of abnormality level of the oil discriminated in the first processing, and third processing of outputting information indicating that the oil analysis involving oil extraction is necessary to other terminal if it is determined that the oil analysis involving oil extraction is necessary in the second processing.