Car overheats: just replaced water housing unit,

sounds like you have a clog. have your system flushed they may be able to unclog it. unless it's in your radiator then that may call for that to be replaced. if the hose on the right side of the engine goes to the top of your radiator double check your coolant level. you could be low and by the time it's done pressurizing and cooling it all drains back into the radiator and the block leaving the hose empty..

Low coolant could cause the overheating because it's forced back through so quick it doesn't have time to cool off much as it passes through the radiator