Polyorganosiloxane composition X that is crosslinkable into elastomer in the presence of moisture provided by the ambient air or by prior addition of water, via polycondensation reactions comprising: A) at least one polyorganosiloxane A comprising at least one alkoxylated group and consisting of identical or different siloxyl units, of formula: b (R 4) a SiO [4-(a+b)]/2 in which: • the symbol Z = [-(OCH 2 CH 2) c -OR 5], with c=0 or 1, • a= 0, 1, 2 or 3; b= 0, 1, 2 or 3, a+b= 0, 1, 2 or 3, • the symbol R 4 represents a C 1 to C 13 monovalent hydrocarbon-based radical, • the symbol R 5 represents a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally comprising an ester function, and • with the condition that for at least one siloxyl unit, the index b≥1 such that the polyorganosiloxane A contains at least one alkoxylated group Z, B) optionally at least one polyalkoxylated silane B of formula: (R 2) z Si(OR 3) (4-z) in which: - z = 0 or 1, - the symbol R 2 represents a C 1 to C 13 monovalent hydrocarbon-based radical, and - the symbols R 3, which may be identical or different, each represent a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally containing an ester function, C) at least one acetylene black D whose function is to absorb an oil used in a powertrain, D) at least one aluminum trihydrate E as mineral filler, E) at least one adhesion promoter F bearing at least one amine function, F) a catalytically effective amount of at least one guanidine G as condensation catalyst, G) optionally at least one unreactive linear polyorganosiloxane H, H) optionally at least one filler I, different from E, and I) optionally at least one additive J such as a coloring base, a pigment or a thixotropic agent, with the additional conditions that • said polyorganosiloxane composition X contains neither any calcium carbonate nor any siloxane containing from 2 to 10 siloxyl units obtained by partial hydrolysis and condensation of a polyalkoxylated silane, and that • the polyorganosiloxane A has a number of units strictly greater than 10, preferably greater than 20 and at most equal to 2000. A) at least one polyorganosiloxane A comprising at least one alkoxylated group and consisting of identical or different siloxyl units, of formula: b (R 4) a SiO [4-(a+b)]/2 in which: • the symbol Z = [-(OCH 2 CH 2) c -OR 5], with c=0 or 1, • a= 0, 1, 2 or 3; b= 0, 1, 2 or 3, a+b= 0, 1, 2 or 3, • the symbol R 4 represents a C 1 to C 13 monovalent hydrocarbon-based radical, • the symbol R 5 represents a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally comprising an ester function, and • with the condition that for at least one siloxyl unit, the index b≥1 such that the polyorganosiloxane A contains at least one alkoxylated group Z, • the symbol Z = [-(OCH 2 CH 2) c -OR 5], with c=0 or 1, • a= 0, 1, 2 or 3; b= 0, 1, 2 or 3, a+b= 0, 1, 2 or 3, • the symbol R 4 represents a C 1 to C 13 monovalent hydrocarbon-based radical, • the symbol R 5 represents a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally comprising an ester function, and • with the condition that for at least one siloxyl unit, the index b≥1 such that the polyorganosiloxane A contains at least one alkoxylated group Z, B) optionally at least one polyalkoxylated silane B of formula: (R 2) z Si(OR 3) (4-z) in which: - z = 0 or 1, - the symbol R 2 represents a C 1 to C 13 monovalent hydrocarbon-based radical, and - the symbols R 3, which may be identical or different, each represent a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally containing an ester function, - z = 0 or 1, - the symbol R 2 represents a C 1 to C 13 monovalent hydrocarbon-based radical, and - the symbols R 3, which may be identical or different, each represent a C 1 to C 6 monovalent hydrocarbon-based radical or an alkoxyalkyl radical optionally containing an ester function, C) at least one acetylene black D whose function is to absorb an oil used in a powertrain, D) at least one aluminum trihydrate E as mineral filler, E) at least one adhesion promoter F bearing at least one amine function, F) a catalytically effective amount of at least one guanidine G as condensation catalyst, G) optionally at least one unreactive linear polyorganosiloxane H, H) optionally at least one filler I, different from E, and I) optionally at least one additive J such as a coloring base, a pigment or a thixotropic agent, • said polyorganosiloxane composition X contains neither any calcium carbonate nor any siloxane containing from 2 to 10 siloxyl units obtained by partial hydrolysis and condensation of a polyalkoxylated silane, and that • the polyorganosiloxane A has a number of units strictly greater than 10, preferably greater than 20 and at most equal to 2000.