Patent claim: The use of claims 1 or 2 where the composition comprises an oil of lubricating viscosity in a major amount containing 50 massor more of a basestock containing greater than or equal to 90saturates and less than or equal to 0.03sulphur.

Related passage: The dispersant can be any suitable dispersant or mixture of multiple dispersants for use in a lubricating engine oil.In one embodiment the dispersant is an ashless dispersant such as an ashless dispersant that comprises an alkenyl or alkylsuccinimide or a derivative thereof such as a polyalkylene succinimide preferably polyisobutene succinimide.In another embodiment the dispersant is an alkali metal or mixed alkali metal alkaline earth metal borate dispersion of hydrated alkali metal borate dispersion of alkalineearth metal borate polyamide ashless dispersant benzylamine Mannich type dispersant phosphoruscontaining dispersant or combination or mixture thereof.These and other suitable dispersants have been described in Mortier et al.Chemistry and Technology of Lubricants 2nd Edition London Springer Chapter 3 pages 8690 1996 and Leslie R.Rudnick Lubricant Additives Chemistry and Applications New York Marcel Dekker Chapter 5 pages 137170 2003 both of which are incorporated herein by reference in their entirety.In a preferred embodiment the dispersant is a succinimide or a derivative thereof.In another embodiment the dispersant is a succinimide or derivative thereof which is obtained by reaction of a polybutenylsuccinic anhydride and a polyamine.In another embodiment the dispersant is a succinimide or derivative thereof which is obtained by reaction of a polybutenylsuccinic anhydride and a polyamine wherein the polybutenylsuccinic anhydride is produced from polybutene and maleic anhydride such as by a thermal reaction method using neither chlorine or a chlorine atomcontaining compound.In another preferred embodiment the dispersant is a succinimide reaction product of the condensation reaction between polyisobutenylsuccinic anhydride PIBSA and one or more alkylene polyamines.The PIBSA in this embodiment can be the thermal reaction product of high methylvinylidene polyisobutene PIB and maleic anhydride.In another preferred embodiment the dispersant is a primarily bissuccinimide reaction product derived from PIB having a number average molecular weight Mn of about 5003000 such as about 6002800 about 7002700 about 8002600 about 9002500 about 10002400 about 11002300 about 12002200 about 13002100 or even about 14002000.In another preferred embodiment the dispersant is a primarily bissuccinimide reaction product derived from PIB having a Mn of at least about 600 at least about 800 at least about 1000 at least about 1100 at least about 1200 at least about 1300 at least about 1400 at least about 1500 at least about 1600 at least about 1700 at least about 1800 at least about 1900 at least about 2000 at least about 2100 at least about 2200 at least about 2300 at least about 2400 at least about 2500 at least about 2600 at least about 2700 at least about 2800 at least about 2900 at least about 3000.In one preferred embodiment for example the dispersant is a primarily bissuccinimide reaction product derived from 1000 Mn PIB which succinimide in another preferred embodiment is subsequently borated to achieve a boron concentration of about 0.13 wt.such as about 12 wt.such as 1.2 wt.in the succinimide.In another preferred embodiment the dispersant is a primarily bissuccinimide reaction product derived from 1300 Mn PIB which succinimide in another preferred embodiment is subsequently borated to achieve a boron concentration of about 0.13 wt.such as about 12 wt.such as 1.2 wt.in the succinimide.In another preferred embodiment the dispersant is a primarily bissuccinimide reaction product derived from 2300 Mn PIB which succinimide in another preferred embodiment is subsequently reacted with ethylene carbonate.