This standard describes the requirements for commercial intake and exhaust valve stem seals used in automotive engine applications utilizing gasoline fuel and gasoline/alcohol fuel blends. Three (3) different types of valve stem seals are described herein. One hundred percent (100%) virgin elastomer is required in compound formulations. No reclaimed Fluorocarbon Rubber (FKM) is allowed.

Material Description.

• Type 1: Fluorocarbon rubber (FKM) for gasoline fueled engines.

• Type 2: Fluorocarbon rubber (FKM) for gasoline and ethanol blended fuels.

• Type 3: Fluorocarbon rubber (FKM) for gasoline and methanol blended fuels.

Symbols. Not applicable.

Applicability. Engine valve stem seals.

Remarks. The materials and constructions described in this standard are capable of operating in a -13 °C to 225 °C environment as defined by ASTM D1329 (TR10) and SAE J2236 respectively. FKM compounds meet these requirements. Seals of this construction and material have been demonstrated to work well at cylinder head temperatures of -40 °C. At this temperature, the temperature transitions occur rapidly enough to not impact material integrity.