From 06:41 -Dean is working on a completely different car. The body trim is different and the interior is white.
When Dean "turns on" the steam in the fun-house, he is actually turning the line off. When you have a handle on a pipe like that pulling it perpendicular to the pipe shuts it off.
After speaking with Ellen, Sam tells Dean that the rakshasa can be killed by a dagger of "pure brass". Brass cannot be "pure", as it is an alloy of copper and zinc. What Ellen may have meant is a dagger made of solid brass rather than a dagger that is merely brass plated.
When Dean takes Jo's rifle away he opens the action, ejecting the cartridge in the chamber. However he then closes the action, which just fed another live round into the chamber, thereby making the rifle ready to fire again. As he is an expert on firearms Dean should have known this and therefore just left the action open.
Ash states that MIT is "a school in Boston." MIT is actually located in Cambridge, Massachusetts, which is a small (but heavily populated) city next to Boston; the Charles River separating the two.