Polymeric lubricant additive designed to enhance anti-wear, anti-oxidancy, and dispersancy thereof

A lubricating oil composition comprising a major amount of an oil of lubricating viscosity and a minor amount, effective to impart viscosity index dispersancy, anti-oxidant, dispersancy, and anti-wear properties to said oil, of a polymeric lubricant additive composition prepared by the steps comprising:

• a) reacting a polymer prepared from ethylene and at least one (C.sub.3 -C.sub.10) alpha-monoolefin and, optionally, a polyene selected from non-conjugated dienes and trienes, comprising from about 15 to 80 mole percent of said ethylene, from about 20 to 85 mole percent of said (C.sub.3 -C.sub.10) alpha-monoolefin and from about 0 to 15 mole percent of said polyene, and having an average molecular weight ranging from about 5,000 to 500,000, with at least one olefinic carboxylic acid or acid anhydride acylating agent to form one or more acylating reaction intermediates having a carboxylic acid or acid anhydride acylating function within their structure;
• and
• (b) reacting said reaction intermediate in with an aminothiadiazole represented by the formula:
• ##STR5## wherein R.sub.1 is H2 or a (C.sub.1 -C.sub.10) alkyl radical selected from the group consisting of alkyl, alkenyl, alkoxyl, aralkyl alkaryl, hydroxyalkyl or aminoalkyl, to produce said polymeric lubricant additive.