If the engine went under water so did everything else such as the transmission, front and rear differentials and all of the electronics. If you intend to continue to drive the vehicle it will become a money pit.
a Flood
The flood plain
Your car's engine most likely got flooded when the water covered your car.
You are. Don't drive through a flood. A car engine was not intended to be submerged in water, particularly dirty flood water.
what is the word for when a land has been covered with water?
flood
Engine, not motor, and that depends on your insurance policy. If you don't have flood insurance specifically, flood damage is typically not covered.
Flood planes
Driving through flood water would cause the ignition to fail and stall the engine.
what is the level or nearly level land that borders a river and is covered by river water in flood time
a flood
A 'floodplain'.