Loctite gasketing sealants and compounds loctite si 5926 loctite si 5926 is a multi purpose flexible silicone sealant that cures on exposure to moisture in the air to form a tough rubber gasket it resists aging weathering and thermal cycling without hardening shrinking or cracking typical applications include valve covers timing gear covers differential covers oil pans transmission pans water pumps and thermostat housings loctite si 5926 is typically used in applications with a se