That's the thing that lets air and fuel into the engine.
"If this one's big, we're better off here, at least until I can get into the engine."
He put a round into the engine and brought the guy down.
I walked out with him and we climbed into the engine.
Less air and fuel can be drawn into the engine.
This air is at the highest part of the cooling system, so it will not get into the engine and cause trouble.
The car broke into two pieces, the tub and the engine.
Looking into the engine, she saw the cobra in two pieces, quite still.
Going to stand beside him, she too peered into the engine.
For a moment, he leaned into the engine again, presumably to look at the black radio box.