| abstract |
The present invention is directed to lubricating oils exhibiting improved resistance to oxidation and deposit/sludge formation comprising a lubricant base oil and catalytic antioxidants comprising an effective amount of a) one or more polymetal organometallic compound; and, b) effective amounts of one or more substituted N,N′-diaryl-o-phenylenediamine compounds or c) one or more hindered phenol compounds or both, to a method for improving the antioxidancy and the resistance to deposit/sludge formation of formulated lubricating oil compositions by the addition thereto of an effective amount of the aforementioned catalytic antioxidants, and to an additive concentrate containing the aforementioned catalytic antioxidants. |