If it happens intermittently, it is caused by a broken tooth or teeth on the engine ring gear. Thus when the starter solenoid throws the pinion gear backwards, the pinion and ring gear will not engage. In some rare cases the pinion gear can come off or the solenoid itself fails, yeilding the same result. You can test this by putting the car into gear and moving it slightly to move the ring gear (in some cars). Sometimes opening the drivers door and jumping up and down on the door sill can rock the engine enough to move the ring (again in some cars). The car might start. The only fix for this ultimately is to replace the ring gear.
If you attempt to start your car and a 'whistle' noise is likely the Bendix on the starter spinning, spinning very fast because it has not come out of the it's housing and meshed with the flywheel gears. "Bendix" is a brand name for the starter drive.
Crank Shaft.
The noise is the teeth on the flywheel grinding on the teeth of the starter. Check to see if the starter is loose, this is the most common cause of that noise.
You need to check your starter or your starter selenoid.
When a starter goes completely out then the engine will not turn over. A starter that is going bad could start sometimes or make considerable noise.
starter motor slipping! replace or rebuild!
could be bad cells in the battery, but my bmw ended up having a seized motor, starter was engaging and clicking because it couldnt turn the engine. try putting a socket on the engine crank pulley to see if engine will rotate
The starter could grind if the bendix is sticking
The starter should only be making noise if you attempt to start the car and the starter is going bad. It is possible that the remote starter is bypassing the mechanical starter. Starters are very easy to replace. Be sure to disconnect the car battery before doing so.
Most starting problems will be caused by a faulty relay or solenoid where you will only hear a clicking sound when trying to start the vehicle or a low battery in which case you will hear a buzzing-type rapid clicking noise. Ocassionally a starter does go bad in which case what you are listening for is a whirring noise (bad starter drive) where the starter will turn but not engage the flywheel, or a grinding noise also known as dragging (worn bushings) which is diagnozed by the starter turning very slow. If there is a "clunking" noise while attempting to start the engine, the starter drive gear may be worn and "spinning" on the flywheel without engaging, or the gear and/or flywheel may have damaged teeth. Also, there may be a case of a starter being burnt out in which case you have to remove the starter and hook it up direct to see if it will turn.
in my experiences if its making no noise or a humming noise than its probably the starter but check the starter relay first. You mighy also check for loose, broken, or corroded wiring, or a burnt-out fusible link.
If the hum is more like a whirring or spinning noise, the starter drive, also known as bendix, needs to be replaced.