My 96 2.5 Tl is making strange noise from the engine.It sounds like chattering /whistling sound.The noise is coming from the engine somewhere around the back.Also the noise is loud once I start the car, once i get into higher rpms it gets quieter and disappears slowly after about half hour of driving, sometimes it doesn’t disappear and sometimes it goes away in 1 minute after starting the car.Also my car drives just fine; performance is the same.I have recently replaced the starter and thats when the noise started to show up.
I've taken my car to a few mechanics and nobody seems to know what it is..Any ideas what can it be? I am totally clueless...

 

I would pull the starter, possibly a weak spring, sounds like starter drive gear is still "touching" the flywheels ring gear. 94