A method of making a diluted chain extended organopolysiloxane containing polymer comprising the steps of: (a) reacting a pre-formed polymer with a chain extender reactable with terminal groups of the polymer, said chain extender being a silane or short chain siloxane having an average chain length of from 2 to about 25 with two reactive end groups designed to react with the terminal groups of the pre-formed polymer, selected from the group of (i) a Diacetamidosilane, a diacetoxysilane, a dichlorosilane, a diaminosilane where each amino group has one or two N-H bonds per nitrogen; a dialkoxysilane, a diamidosilane, a hexaorganodisilazane, a diketoximinosilane; (ii) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and having at least two acetamido or acetoxy or alkoxy or amido or ketoximo substituents per molecule, (iii) a compound of the structure ZMe 2 SiO(Me 2 SiO) y SiMe 2 Z or ZMe 2 Si -Y-SiMe 2 Z where Z is a heterocyclic Si-N group Y is a divalent hydrocarbon radical selected from the group consisting of --(CR 2)m -- or -C 6 H 4 -, y is.0 or a whole number, and m is 2 to 6 inclusive and R is a monovalent hydrocarbon group; (iv) a dialkenylsilane, a dihydrosilane, (v) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-alkenyl bond per terminal group, (vi) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-H bond per terminal group; in the presence of a diluent material selected from polyisobutylenes, phosphate esters, polyalkylbenzenes, linear and/or branched alkylbenzenes, esters of aliphatic monocarboxylic acids, linear or branched mono unsaturated hydrocarbons such as linear or branched alkenes or mixtures thereof containing from 12 to 25 carbon atoms; and/or mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils and/or cyclic (naphthenic) mineral oils and mixtures thereof; a suitable catalyst and optionally an end-blocking agent; and (b) where required quenching the chain extension process; wherein the diluent material is substantially retained within the resulting diluted organopolysiloxane containing polymer. (a) reacting a pre-formed polymer with a chain extender reactable with terminal groups of the polymer, said chain extender being a silane or short chain siloxane having an average chain length of from 2 to about 25 with two reactive end groups designed to react with the terminal groups of the pre-formed polymer, selected from the group of (i) a Diacetamidosilane, a diacetoxysilane, a dichlorosilane, a diaminosilane where each amino group has one or two N-H bonds per nitrogen; a dialkoxysilane, a diamidosilane, a hexaorganodisilazane, a diketoximinosilane; (ii) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and having at least two acetamido or acetoxy or alkoxy or amido or ketoximo substituents per molecule, (iii) a compound of the structure ZMe 2 SiO(Me 2 SiO) y SiMe 2 Z or ZMe 2 Si -Y-SiMe 2 Z where Z is a heterocyclic Si-N group Y is a divalent hydrocarbon radical selected from the group consisting of --(CR 2)m -- or -C 6 H 4 -, y is.0 or a whole number, and m is 2 to 6 inclusive and R is a monovalent hydrocarbon group; (iv) a dialkenylsilane, a dihydrosilane, (v) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-alkenyl bond per terminal group, (vi) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-H bond per terminal group; in the presence of a diluent material selected from polyisobutylenes, phosphate esters, polyalkylbenzenes, linear and/or branched alkylbenzenes, esters of aliphatic monocarboxylic acids, linear or branched mono unsaturated hydrocarbons such as linear or branched alkenes or mixtures thereof containing from 12 to 25 carbon atoms; and/or mineral oil fractions comprising linear (n-paraffinic) mineral oils, branched (iso-paraffinic) mineral oils and/or cyclic (naphthenic) mineral oils and mixtures thereof; a suitable catalyst and optionally an end-blocking agent; and (i) a Diacetamidosilane, a diacetoxysilane, a dichlorosilane, a diaminosilane where each amino group has one or two N-H bonds per nitrogen; a dialkoxysilane, a diamidosilane, a hexaorganodisilazane, a diketoximinosilane; (ii) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and having at least two acetamido or acetoxy or alkoxy or amido or ketoximo substituents per molecule, (iii) a compound of the structure ZMe 2 SiO(Me 2 SiO) y SiMe 2 Z or ZMe 2 Si -Y-SiMe 2 Z where Z is a heterocyclic Si-N group Y is a divalent hydrocarbon radical selected from the group consisting of --(CR 2)m -- or -C 6 H 4 -, y is.0 or a whole number, and m is 2 to 6 inclusive and R is a monovalent hydrocarbon group; (iv) a dialkenylsilane, a dihydrosilane, (v) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-alkenyl bond per terminal group, (vi) a polydialkylsiloxane having a degree of polymerisation of from 2 to 25 and at least one Si-H bond per terminal group; (b) where required quenching the chain extension process;