My 2008 RX 350 seems to generate and retain excessive heat inside the cabin - coming from under / behind dashboard. I can park the car inside a cool garage, and many hours later it will still be mildly warm. Of course, it's much more noticeable in the summer.

With the AC and Auto off, and the fan in either the internal circulating and outside air modes, vent air seems hotter than the source.
Is this excess heat normal for the RX? Does its internal combustion engine throw off so much excess energy? Any comments / thoughts appreciated.

P.S. thanks to posters across many topics; I learn a lot from other folks' sharing.