I've been having a lot of problems with my Lexus lately. My boyfriend heard a squeaking in the engine and replaced the fan belt. The squeaking continued but that's not the worst of our worries. When he turned the car on this morning it made a quick and loud rattling noise like a person running with a wrench hitting it against a metal fence and we have no idea what could have caused it. My boyfriend is outside looking under the car, pissed off and frustrated, we could use all the help we can get. PLEASE HELP!