Paper and cork gaskets often fail, or are hard to find for older engines. Gasket maker is a paste applied to clean metal surfaces. It cures upon contact with air moisture to form a tough rubber seal. RTV silicone is available in color-coded types, such as Black for oil resistance, Grey for high torque, and Red for high temperatures. Apply a 1/8-inch bead, assemble the parts finger-tight, wait an hour, and then torque the bolts to spec. Let it cure for 24 hours before filling the engine with fluid.
Mechanic Glossary
Gasket Maker
A liquid or paste sealant, typically RTV silicone, that dries to form a custom, flexible gasket between engine mating flanges.
Frequently Asked Questions
RTV stands for Room Temperature Vulcanizing, meaning the silicone cures and hardens at normal room temperature when exposed to air moisture.
No. Household silicone cannot withstand the high temperatures, oil, and chemicals found inside an engine, and it will quickly leak.
Most RTV sealants require a full 24 hours to cure completely. Running the engine sooner can blow out the wet sealant and cause leaks.