Reply to "Toyota Engine Oil Sludge/Failure"

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You must be Charlene Blake's husband, or mechanic.

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Unlike older generation Group III stocks, which can have more than five percent aromatics, modern Group III stocks also undergo subsequent severe hydrofinishing after hydrocracking and hydroisomerization. Consequently, they have exceptional purity with aromatics levels of much less than one percent, resulting in high thermal and oxidative stability. On the other hand, PAO stability depends largely on residual olefin content, which can be present at significant levels - up to five percent. Even though PAOs have generally excellent oxidation stability, in many applications such as engine oils or high-temperature compressor oils, their performance is matched by modern, severely processed Group III base oils.

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Oxidative, thermal and hydrolytic degradation will change the base oil's chemical and physical properties, which then alters the lubricant's performance properties.
One of the most common forms of base oil degradation is oxidation. It occurs when oxygen reacts with the lubricant's base oil, which is typically a hydrocarbon. When the oil becomes oxidized, some hydrocarbon molecules are transformed into acid and sludge,