I drive a BMW 525i, recently hasn't been starting up, I drove to see my friends once and was fine, when I left them I try to start and would not dare to start, so checked on the radiator, the was no water. But it never showed any signs of heating up, I put water on, tried and never moved, I tried taking a metal stick and hitting the starter and it now clicking and I can see the engine wanting to turn but won't, can anyone help me please, I replace a battery, and my car is automatic. What could the problem?
Either the starter is bad, or the engine overheated severely and has galded the pistons causing it to resist being turned by the starter.
Try a new starter, if symptoms are the same, see how hard it is to turn the engine over using a breaker bar and socket, use the front crankshaft damper bolt to turn the engine clockwise, can you turn it fairly easily? If not the engine has seized due to severe overheating, time for a new engine.
This is what happens when a piston gets too hot and galling happens, metal from the piston is transferred to the cylinder walls and seizes the motor.