Does somebody know how it is possible to identify the engine oil grade quality by a lab check. I mean the difference between API CH4 or CG4 or CI4 15w-40 .
More engine test requirements are included in the CI4 catagory and is done by incorporating more chemicals as additives.In this catagory, dispersants and ditergent additives are in higher percentage.The test results of the used oils of this catagory shows a high TBN and high TAN.
new diesel engine oil has high TBN value and almost zero Tan value because of the sulphur formation after being started to be used. Used diesel oils have high tan but low tbn value( Sulphur will form H2S. Does it correct?