The three longer screws go all the way through to the head, and hold the assembly on. If you have all the screws out, the assembly will be held in place by the hoses, and will move some. Now the halves can be separated. Use a large screwdriver, there is a spot on top wher you can pry. The halves will pop apart, and you will get some coolant . If you did not remove the short L-shaped hose from the thermostat, you may want to. I could not get the pump out otherwise. Good Luck
Al