So our 2003 Dodge Sprinter Passenger Van has back doors that leak (when it rains a ton) and the squeak while driving (incredibly annoying for a new driver like me). My dad greases the hinges every few months but they still squeak, rattle, and leak. Have any of you had this problem before or have ideas that might help to fix it?

Also the lock on the side door has malfunctioned pretty much since we bought the van. I clean the contacts on the doors every once in a while but that doesn't completely eliminate the problem. Any ideas?