Loctite SI 5135 Silicone Gasket Sealant (Grey 100 ml) SpecificationsLoctite SI 5135 sealant is used to make flexible flange gaskets by curing when in contact with moisture in the air. With its excellent adhesive properties it is ideal for filling large gaps (up to 1 mm) and is a high-performance sealant for mechanical assemblies.This one-component silicone paste is used on metal stainless steel aluminium plastic or polycarbonate flanges where good resistance to oils is required. Typical applications include valve covers timing gear covers differential covers oil pans transmission pans water pumps and thermostat housings.