These oils will always have the correct thickness when hot and will still be too thick at startup as with all oils of all types, regardless of the API / SAEviscosity rating.
The evolution of viscosity classification of SAE J300 engine oil is explained, while main influence factors promoting the upgrading are discussed in this paper.
介绍了SAE J 300内燃机油粘度分类的沿革，阐述了促进其升级换代的主要影响因素。
3
Poor quality of the base. oil. Most likelyuse of incorrect viscosity (SAE class)