Lubricating oil from the engine was out of service owing to the continuous operations, you should replace the new engine oil. Performance of engine oil was changed as the sake of the impurities’ coming in, it will produce harmful substances. So you should consider the below issues for checking if it need to be replaced.
Viscosity: If oil’s viscosity is too high, the low temperature star-up and pump’s performance changed will let the cooling effect decreased, adversely affect the friction and wear of the engine.
If oil’s viscosity is too low, the lubrication performance will decreased, it will also enhance the wear of the engine, therefore, when the viscosity index reach to 100 degree, it should be scrapped.
Water: Due to the wide temperature range of the engine, it is inevitable to enter a small amount of cooling water in the oil. Therefore, the maximum moisture content of engine oil has been set at 0.5%. Exceed part will be free water.
Impurities: From n-pentane and benzene insoluble matter can generally determine the oil pollution.
Acid Value: Engine bearings are the most susceptible to acid corrosion. The new oleic acid value sometimes exceeds the 0.5’s standard, so you should confirm the oil’s maximum acid value from the oil additives and changes in acid value.
Flash point: flash point is also an indicator of the oil scrapped.
After the oil is polluted, it is filtered by a vacuum oil purification to recover the original oil. TYA lubricating oil purification is a professional plant for waste lubricating oil dehydration, impurity removal, water-soluble acid removal, and improve the breakdown voltage value after treatment.