Therer is and on and off clicking aound coming from my engine. It goes on for 3 seconds, off for 4, and back and forth. Sometimes it happens, sometimes it doesn't. Have not been able to associate it with any particular temp, time of day, fan, AC, Gear, Etc. Just sometimes it clicks back and forth. Sometimes it doesn't. I found the clicking was caused by a triangular end piece at the bottom right of the engine attached to the serpentine belt. Specifically when the piece switched between rotating and not rotating. I'm only average with engines, so I don't know exactly what part of the engine that is. Particularly because this is my first Ford and Mustang. Please see attached pictures and tell me what you think.
History: Vehicle is a rebuilt salvage. Serpentine belt recently replaced. Passed California Smog.
2006 Ford Mustang 4.0L V6 Automatic