Squeaking Sound When ICE is Fully Warmed Up

Hi Everyone,

I have a 2018 Prius Prime and I noticed some strange squeaking/rubbing sounds only when the ICE is on and after ICE has fully warmed up, after giving the engine some "exercise" such as driving on the freeway for at least 30 minutes and/or after climbing a steep hill. I will try to describe the noises as best as I can.

- car drives perfectly and smoothly in EV mode with ICE off - no noises at all
- no squeaking/rubbing noises at all when ICE is on and is still warming up, and when ICE is on and driving in city stop and go traffic
- squeaking/rubbing noises only occur at slow speeds, less than 40 km/h or 25 MPH, when ICE is on and is fully warmed up, and the squeaks occur when the angle of the car changes
- chugging/rubbing noises heard when ICE is fully warmed up, and right before car comes to a complete stop, whether brakes are used or not to stop, and again when starting to move again after a full stop, even before the ICE switches on to give power to the car
- all noises gone again after the engine is allowed to rest for a while, even with ICE on, until the car is given some "exercise" again

Any ideas of what causes these sounds? Are these sounds actually normal or of concern? Thanks for helping Prius Student.

 

Thank you for your responses! I had the car lifted up on a hoist and found that the heat shields were loose and likely making contact only when the engine is fully warmed up. I tightened the loose heat shields and the noise is gone.