HELP! 06 NPR 5.2 diesel. It can sit over night, and be started to be used in the early morning, with no problem. Yet, if it is not started the next morning, within about 12 hours of shutting down, it begins to leak diesel fuel out of the rear of the tank. It appears, it may be a vent on the rear of the tank??? Also, when filling up, it may begin to leak once full, until it is started and running.