99 taurus won't crank

My friend has a 3.0 vulcan taurus that acts like the engine is locked up at times, other times it starts and runs well with no unusual noises and the car drives well. no white smoke, no bubbles from the radiator. they had a starter put on and the same thing.the battery cables get really hot like the engine is really locked up or a shorted starter. other than maybe something wrong with the flywheel, is there anything odd on this car that would cause this? thanks

The engine could be hydrolocking due to leaky fuel injectors, bad head gasket, etc. Sometime when the engine seems locked, have you friend pull the spark plugs, cover the holes with rags to catch any liquid, and attempt to crank the engine over. If the engine now cranks fine and a bunch of stuff comes out of the cylinders, examine the stuff and attempt to determine what it is. Is it most like coolant, fuel, or oil?

If the engine still seems locked, then you'll probably want to pull the starter and attempt to rotate the engine crankshaft (still with the spark plugs removed). If the engine spins fine with the starter removed, inspect the starter and interface with the flywheel for damage.

-Rod

The engine could be hydrolocking due to leaky fuel injectors, bad head gasket, etc. Sometime when the engine seems locked, have you friend pull the spark plugs, cover the holes with rags to catch any liquid, and attempt to crank the engine over. If the engine now cranks fine and a bunch of stuff comes out of the cylinders, examine the stuff and attempt to determine what it is. Is it most like coolant, fuel, or oil?

If the engine still seems locked, then you'll probably want to pull the starter and attempt to rotate the engine crankshaft (still with the spark plugs removed). If the engine spins fine with the starter removed, inspect the starter and interface with the flywheel for damage.

-Rod
Thanks for the info, he said the plugs were out and it wouldn't crank, I'll have him pull the starter. regards, Les