Patent ID: 7875580

Claim:
A method of reducing wear in an automotive engine by the addition to the engine an automotive engine oil comprising a base oil and an ester which is the reaction product of (a) at least one polyfunctional alcohol; (b) a dimer fatty acid having a dimer content of greater than 94% by weight; and (c) at least one of an aliphatic dicarboxylic acid having 5 to 18 carbon atoms and an aliphatic monocarboxylic acid having 5 to 24 carbon atoms; wherein the resultant ester has a kinematic viscosity at 100° C. ranging from 1500 to 5000 mm 2 /s and a non-polarity index (NPI) NPI = total ⁢ ⁢ number ⁢ ⁢ of ⁢ ⁢ carbon ⁢ ⁢ atoms ⁢ × ⁢ molecular ⁢ ⁢ weight number ⁢ ⁢ of ⁢ ⁢ carboxylate ⁢ ⁢ groups ⁢ × ⁢ 100 of at least 500; and wherein the automotive engine oil has a phosphorus level of no more than 0.08%.