Engine Noise

Depends on what type of car and engine and exhaust system and the current state of repair these are all in...On my Mustang, it's the exhaust outlet....

In most new cars it's the sound of the tires on the road. The only sound you hear from the engine is the fan cooling the radiator. Performance cars are another matter.

Only when it is idling, you only hear fan noise. When accelerating, typical car engine noise is more than any other noise.

I find that is the exhaust pipe (being that it is one of its primary functions in a vehicle), unless the car is old/defective in which case the most noisy part could be (for example) part of the interior trim.

Additionally it depends on where you are listening (inside the vehicle, under the hood with the bonnet open, outside the vehicle, outside the vehicle at a distance).

Do you have access to a car you can listen to? Does the car stereo count?

Can you please provide more information as I think there is someting fundamental we are missing that you have not told us yet.

I meant engine noise as listened from outside the car.