Seal materials used for high temperature applications are usually made from

• A. Silicone
• B. Nitrile
• C. Fluorocarbon
• D. Viton

Answer: (B)

For high-temperature sealing, you want a material that stays elastic and resists breakdown in heat and in the presence of automotive fluids. Fluorocarbon elastomers (FKM) fit this need best because their chemical structure gives excellent thermal stability and broad chemical resistance, so they maintain sealing performance even well above room temperature. Viton is a well-known brand name for this fluorocarbon family, so mentioning fluorocarbon covers that material category and its high-temperature capability.

Nitrile elastomers (NBR) are great for oil resistance and cost, but their temperature tolerance is much lower, so they don’t hold up as well in high-heat environments. Silicone can tolerate high temperatures too, but in many automotive sealing applications it doesn’t offer the same chemical resistance or mechanical properties as fluorocarbon elastomers, so fluorocarbon remains the preferred choice for high-temperature seals.