The ILSAC GF-5 industry standard and the GM dexos 1™ specification both require an oil to prevent sludge formation in the Sequence VG engine test.
Unfortunately, their most demanding target still allows for a measurable amount of potentially dangerous sludge deposits to form in the engine, coating critical engine parts and oil channels. An oil meeting their targets could still produce in excess of 150 ml of sludge or alternatively the equivalent of a bottle of known brand hot
PUREZONE 100% Synthetic products set a different standard when it comes to the acceptable amount of sludge that an oil can produce … 0.05 ml. If an oil can be produced that creates almost no sludge, which would you prefer to use in your engine?