Good evening all. I have to replace the radiator cap on the coolant tank and don't know for sure if 10 or 15 PSI.<br/>We have a 2009 Nimbus with the Cummins ISM 500.<br/>I have not checked with FOT for a part number but could be NAPA.<br/>Not sure<br/>Does anyone out there know a part number.<br/>We are leaving for New Mexico next week and don't want to worry about that.<br/>Thanks <br/>C. Knight