Before cleaning, check for leaks, damage and cracks.Clean cylinder head and oil passages. Check cylinder head for flatness .Cylinder head must be flat within:Standard dimension = less than 0.05 mm (0.002 inch.)Service Limit = 0.2 mm (0.008 inch.)Grinding Limit = Maximum of 0.2 mm (0.008 inch.) is permitted. 0.20 mm (0.008 in.) MAX is a combined total dimension of the stock removal limit from cylinder head and block top surface (Deck) together.