After my engine is warmed up and been driving, and I park it in the garage...I smell the vague scent of hot rubber coming from the engine compartment. There is no smoke, and it smells of hot rubber (not burnt rubber)---almost like a piece of rubber is being exposed to something very hot--not hot enough to burn...but hot enough to cause a heated rubber scent for the engine compartment. It can not be smelled from inside the car while driving. I have asked my Toyota dealer about this, they they said it is normal...however..that scent never used to be there when it was new. What might it be?