RTV silicone rubber.
The company's 3-0115 automotive sealant is a one-part, self-priming RTV silicone rubber designed for automotive powertrain sealing applications. Formulated for sealing automotive flanges, coolant systems, engine blocks, engine and transmission oil pans, axle cover seals and where immediate pressure leak testing is required, the 3--0115 sealant is said to provide an elastomeric seal that is resistant to most automotive powertrain fluids. The 3-0115 sealant is said to withstand in-line pressure leak testing in assembly operation and provides low oil foaming properties when in contact with fluids and oils. (Dow Coming) www.dowcorning.com