2001 gtx DI overheating

[ceez]

just bought......once i put in the water the first i noticed was the pisser not pissing. Isped up to about 40mph and it started beeping that its overheating, quickly slowed down and shut off engine. What i first tried was the cooling hose leading to the engine, blew through it no blockage, then i took out the exhaust and notice some white residue/corrosion/salt? where the water should be exiting from the cooling loop in the engine to the exhaust. I tried to blow air and water under pressure through the engine block and it didn't' come out the top end, begin coming out in the back. Is it clogged? what do i do?