2S3080 Cap Fits Caterpillar D4D D6C 977K 977LOne New Aftermarket Replacement Pressure Relief Cap Fits Caterpillar (Fits CAT) Track Type Tractors and Loaders This aftermarket replacement 2S3080 is a coolant system pressure relief cap (also cataloged as Cap As Coolant and Cap As Pressure Relief) Fits Caterpillar (Fits CAT) heavy construction equipment. It seats on the radiator or coolant reservoir to maintain proper system pressure and prevent coolant loss during operation. Specifications Part