Elastomer compatibility is an important property of lubricants. When seals degrade oil leakages may occur, which is a cause of concern for original equipment manufacturers (OEMs) because of warranty claims. Leakage is also a concern for environmental reasons. Most often, the mechanical properties and fitting of the oil seals is identified as the source of failure, but there are cases where the interaction between the lubricant and the seal material can be implicated. The performance of seal materials in tensile testing is a required method that must be passed in order to qualify lubricant additive packages. We conducted an extensive study of the interactions between these elastomeric materials and lubricant additive components, and their behavior over time. The physicochemical mechanisms that occur to cause seal failures will be discussed.