Description Replacement O-Ring for Water Bypass Adapters. You can either purchase a Dash 113 or 119 o-ring or try to find one locally. NOTE: If you plan to look for your own, ensure the material is compatible with Ethylene Glycol. RAA/ RBB/ RBC/ RSP Cylinder Heads = Dash 113 O-Ring (smaller) R40 Cylinder Heads = Dash 119 O-Ring (larger)