A polyether having the formulaRX[(C.sub.x H.sub.2x O).sub.n (C.sub.y H.sub.2y O).sub.p Z].sub.m(I)wherein:R is either an alkyl or alkyl phenyl group having from 7 to 30 carbon atoms,X is selected from O, S or N;x is an integer from 2 to 4;y is an integer from 6 to 30;Z is a hydrocarbyl group containing from 1 to 30 carbon atoms;m is 1 when X is O or S or m is 2 when X is N;n and p are such that the polyether contains between 1 and 40% by weight of (C.sub.y H.sub.2y O) units and between 40 and 80% by weight of (C.sub.x H.sub.2x O) units; and the molecular weight of the polyether is between 500 and 3,500. Lubricating oil compositions comprising such polyethers are disclosed. A method of preparing the polyethers is disclosed and comprises preparing a H-capped polyether, preparing an alkali-metal salt thereof and reacting said salt with an alkylating agent.