My LR4 has over 214k miles and has been regularly serviced. I even did the water pump ( couple times) and they replaced the coolant lines that are known to leak. I am hearing a faint whistle from under the hood (closer to the passenger side up in back like near the battery) that is more evident as you turn the car off and it continues like 2 seconds after the engine stops. What could this be? I can try to record it and post the audio here. in terms of performance: the vehicle runs fine however at idle it seems to wavier slightly around 900 - not as smooth as it typically is. is this something serviceable / DIY or should it go into the shop? tried searching but didn't see any other similar threads.