GM 4 Cylinder Valve Cover Gasket | Sierra 18-0347 Seals valve cover to cylinder head on GM 2.5L and 3.0L marine engines. For GM 2.5L 153 CID and 3.0L 181 CID 4 cylinder marine engines Replaces Mercruiser 27-52145, 27-806452, and 27-34041 Replaces Marine Power 0025-101 Replaces OMC 3852693, 912981, and 913277 Replaces Volvo Penta 3852693