[BlackI4se]

What is that big black plastic strip on the I4 (not sure if it is on the 6) that goes from the front of the motor to the back. AT first I thought it was the Air intake but it seems like it isnt since the box is off to the right.

 

[Metallicat]

Alternator cooling duct. 

I don't know how effective it is. Even after leaving the car off for a while, the plastic duct is still very hot to the touch due to the fact that it runs right over the top of the engine.