Hylomar Hylosil Silicone Sealants have been used by major automotive OEMs since 1975 to seal engine flanges, including Ford, Mercedes, and John Deere. They are formulations designed to last for the life of today's extended warranties, and to resist the higher temperatures in today's engines and the friction modifiers and additive packages in today's synthetic motor oils without breaking down.
Hylomar's OEM-specified Hylosil 100 Series Silicone RTVs are made with a neutral curing, sensor-safe amine-cure formulation unlike any other in the American aftermarket.

 

Hylosil 300 Series Silicone RTVs are very high quality acetoxy formulations for general industrial and engineering use.

 

Both formulations are relatively expensive, and are designed for performance and durability. It is easy to formulate a cheaper silicone sealant, by including lower cost fillers, cheaper cross-linkers, and standard polymers. But there are no compromises in our formulations. Just be sure to do an excellent job of surface preparation, and clean away oily spots, for the best results.