hello, has anyone else heard a whistling sound from engine bay after driving and then parking? It goes on for bout a minute. Its not the usual whirling click sound. I took my car into service and mention it to the service writer. He said its the hybrid system. is that true? i cant seemed to find any comments about it anywhere.

any info will be greatly appreciated.

You do know that when you turn off your 450h... you really aren't "turning it off".
Ive heard my car do things 3-4 hours after driving it.


In a nut shell, Yes I've heard that before. Totally normal.

This is the Hybrid System cooling pump. The power electronics and motor still need to be cooled after the car is off because they are a lot more sensitive to heat than the engine. It's basically the same reason why you have to idle a turbo'd engine after some abuse so that you don't cook the turbo bearings.

I was surprised by this noise when I first picked up my 450h, but I've been told that it's normal. I wouldn't worry too much about it. It's just the hybrid system cooling down, and I think it powers the electronics.

thanks for the replies greatly appreciated. I've had this car for bout 4 years and never really notice that whistling sound. I did notice clicks and whirling sounds usually goin on and off for hours. thanks again.