COVER GP-VALVE MECHANISM 2P6516 - Caterpillar

3406, 3408 And 3412 Engines In All ApplicationsReference: This article is a replacement for the earlier article with the same title on Page 9 of the December 1, 1980 Service Magazine. Cancel the original article and use the information that follows.Description of Change: A different O-ring seal is now used where the oil pump suction tube connects to the oil pump on the above engines. The new seal is made of a fluorocarbon rubber, which has a light brown or tan color, and will keep its soft, flexible condition for a longer period of time under compression. The former seal is made of a silicone rubber which has a yellow color. This material can take a permanent shape under compression and let air into the pump suction line.Adaptable As: Direct replacement in this application. The former seals are still available for other applications. Either of two different size seals are used in the different oil lines groups for the above engines. Use a new 5P5846 O-Ring Seal in place of the former 9M9647 O-Ring Seal, or a new 8J4351 O-Ring Seal in place of the former 8M4443 O-Ring Seal.