Neutral Base Stock
There are 2 different processes that can be used to refine crude oil.
Catalytic cracking uses heat to remove impurities and extract gasoline and diesel fuel. Crude is heated to 1900 degrees and the molecule of the oil is broken (cracked) down.
The result is you lose the lubricating qualities of the removed fuels and what's left is damaged product which is susceptible to thinning when exposed to temperature or pressure. It also mixes easily with water (emulsifies) and has a higher flash point.
Solvent Neutral extraction on the
other hand, uses solvents or chemicals instead of heat to refine crude oil. The complete molecule of the oil remains intact. The fuels (gasoline and diesel) are not removed resulting in a "non-cracked solvent neutral base stock" which is vastly superior to crude which have had the fuels removed. It resists thinning even under much higher temperatures and pressures. The result is an oil that can be run for many hours straight with no significant thinning. Oil pressure stays high, resists wash-down from fuel getting past engine rings and contamination of anti-freeze which can also get into the engine. The oil life is greatly increased. Mack Trucks has approved ULX-110 for 40,000 to 50,000 mile change intervals.
API