Loctite SI 587 is used for gasketing and sealing applications for both plant maintenance and small, medium and large-sized OEM. As a formed-in-place gasket/sealant, Loctite SI 587 has been designed to give outstanding performance in typical automotive gasketing applications including valve covers, rocker covers, oil pans, water pumps, end seals, intake manifolds and rear axle housings. - Loctite SI 587 blue high performance RTV silicone gasket maker is a one-part, formed-in-place, RTV silicone that forms tough, flexible gaskets directly on the flange.