The first or second open mortgage on your home can be repaid in full before the deadline but choosing to do this leads to a penalty fee of three months interest. (mortgagebrokerstore.com)
It's meant to close in order to stop air getting into the engine immediately after switching off the engine, then after a few seconds it opens again. (mechanics.stackexchange.com)
It's so simple in fact, that this is all explained in a 5 - second opening cut scene. (thevitalounge.net)