So we all know the 2.5 makes an interesting collection of sounds, particularly at start up, but I'm curious if we actually know what the various components are.
#1 - The whine - I'm kind of assuming this might be the alternator or something else on the belt? I hear it in pretty much every video I've seen of a 2.5
#2 - Clicking - There's a clicking that seems to come from somewhere around the front of the motor. Behind the intake mani perhaps. I'm assuming it's just the valves/cams or maybe the timing chain but I'm not sure. Anyone know for sure?
#3 - Blowing noise on startup - It doesn't seem to do this one very long but I've heard a pretty significant flow of air from somewhere. Like a vacuum cleaner minus the actual pump noise. I've heard an air pump mentioned before so I guess it's that but, again, not sure. Am I correct in thinking that's something to do with SAI?
I know this has all probably been covered at some point or another but searching proved surprisingly unfruitful. Just interested in learning more about this engine. Feel free to throw any other weird noises out there.