Lubricating oil compositions

A method of obtaining viscosity index enhancement in a lubrication composition comprising the step of adding the following to the lubricating composition:

• (i) a hydrocarbyl aromatic which contains at least about 5% of its weight from aromatic moieties and having a viscosity of about 3 to about 50 cSt at 100° C.;
• and
• (ii) an olefinic oligomer of about 2,000 to about 20,000 number average molecular weight and having a viscosity of about 75 to about 3,000 cSt at 100° C.;
• wherein the weight ratio of component (a) to component (b) is from about 1:2 to about 50:1.

A method of obtaining enhanced high-temperature high-shear (HTHS) viscosity performance of a lubricating composition comprising the step of adding the following to the lubricating composition:

• (i) a hydrocarbyl aromatic which contains at least about 5% of its weight from aromatic moieties and having a viscosity of about 3 to about 50 cSt at 100° C.;
• and
• (ii) an olefinic oligomer of about 2,000 to about 20,000 number average molecular weight and having a viscosity of about 75 to about 3,000 cSt at 100° C.;
• wherein the weight ratio of component (a) to component (b) is from about 1:2 to about 50:1.

A method of making lubricant composition Theological properties more Newtonian comprising the step of adding the following to the lubricating composition:

• (i) a hydrocarbyl aromatic which contains at least about 5% of its weight from aromatic moieties and having a viscosity of about 3 to about 50 cSt at 100° C.;
• and
• (ii) an olefinic oligomer of about 2,000 to about 20,000 number average molecular weight and having a viscosity of about 75 to about 3,000 cSt at 100° C.;
• wherein the weight ratio of component (a) to component (b) is from about 1:2 to about 50:1.

A method of obtaining viscosity index enhancement in a low-phosphorus, low-ash, paraffinic lubrication composition comprising the step of adding the following to the lubricating composition:

• (i) a hydrocarbyl aromatic which contains at least about 5% of its weight from aromatic moieties and having a viscosity of about 3 to about 50 cSt at 100° C.;
• and
• (ii) an olefinic oligomer of about 2,000 to about 20,000 number average molecular weight and having a viscosity of about 75 to about 3,000 cSt at 100° C.;
• wherein the weight ratio of component (a) to component (b) is from about 1:2 to about 50:1.