What is the difference between CJ and CK diesel engine oils?

[Pereira]

Diesel engine oils CJ and CK have the following differences: 1. Different grades: The first letter of diesel engine oil is "C", and the grades are CA, CB, CC, CD, CE, CF, CF-4, CG-4, CH-4, CI-4, CJ-4. With each increasing letter, the quality grade of the oil becomes higher, meaning the CJ grade is higher than CI. 2. Different performance: With each increasing letter in the oil quality grade, the performance of the oil is superior to the previous one. Whether it's the stability of the oil (detergency and dispersancy) or the protection performance for the engine (corrosion resistance and oxidation resistance), the CJ grade oil, as the highest level, outperforms the CI grade. 3. Different oil change intervals: Under normal circumstances, the oil change interval for CJ-4 grade oil is 40,000-50,000 kilometers, while for CI-4 it is 20,000-30,000 kilometers.