This SAE Standard was developed primarily for passenger car and truck application@ but may be used in marine@ industrial@ and similar applications. Purpose The purpose of this document is to provide dimensions for the different pressure ratings of bayonet type radiator pressure caps and filler necks. Use of these dimensions will prevent the use of a high-pressure rated cap on low-pressure systems for the small and medium size applications (see Tables 1 and 2 and Figures 1 to 3).