The way i would do it is i would de-attach my hood from the body. Then shift+drag edges inwards from the bumper and fender to make your inner parts that hold the radiator and the pieces that hold the bolts and the strut bars and so on. The main things you see come with the car. And then you can model the engine parts separately and merge them to your model and align them. But be careful when aligning them make sure you keep a good scale.
