The lubricating oil composition of the parent Specification comprising a mineral lubricating oil with a small proportion of a polyvalent metal salt of a substituted or non-substituted aromatic monocarboxylic acid and particularly exemplifying the Ca and Zn salts of di-isopropyl salicylic acid is modified in that the additive comprises certain polyvalent metal and lithium salts of an octadecyl salicylic acid, stearyl salicylic acid or of a mixture of alkylated salicylic acids in which the alkyl groups contain 8 to 18 carbon atoms. The polyvalent metals comprise Al, Be, Ba, Ca, Mg, Co, Ni, Zn, Sr, and Sn. Full details are given of the preparation of the compounds from which the salts are derived (see Group IV), the usual standard methods being employed.ALSO:Octadecyl salicylic acid, stearyl salicylic acid, or a mixture of alkylated salicylic acids in which the alkyl groups contain 8 to 18 carbon atoms are prepared as follows: (1) salicylic acid is reacted with the appropriate olefine or primary, secondary or tertiary alcohol in the presence of a condensing agent such as sulphuric acid, BF3 or ZnCl2 at a sufficiently high temperature. The corresponding phenol may be used and alkylated by this method followed by carboxylation. (2) The alkylated phenol is carboxylated by the Kolbe method by passing CO2 through a boiling xylene solution of the sodium salt of the alkylated phenol. (3) Nuclear acylated salicylic acid, such as stearoyl salicylic acid, are reduced by the Clemmensen method, i.e. by means of zinc wool and HCl in the presence of a proportion of anisole to liquefy the stearoyl compound. (4) Salicylic acid is reacted with stearyl chloride dissolved in nitrobenzene in the presence of AlCl3. Laboratory details are included in all the above preparations. The preparation of metal salts of the above compounds, mainly polyvalent metals and lithium, is also described, particularly barium octadecyl salicylate, beryllium stearyl salicylate and mixed calcium salts of C8-C9 alkyl salicylic acid.