A friend just ahd this happen. He burned a pump and the impeller blades were all through the coolers. So we cleaned it out, still no water flow. Turns out there was a plastic flush "T" in the intake hose with a plunger to shut off the raw water when you hook up a hose. The plunger stuck in the down position due to the suction when he went aground and was blocking the intake line, shutting off the intake water. Have them look for that.