True Dat, cars do get warmer when parked then driven. Our old 82 vw rabbit would pop the electric fan on 5 minutes after parking and shut it off a few minutes later.
I noticed the ac in my scion xa wasnt as cold as it could be and the other toyota products had 2 cooling fans where as I had one. I added a second one to make it colder and it did so, lost 4mpg. I use to leave the fan on for short trips inside stores to aid in reducing under hood temps.