2017 Sierra noise

[tlr_42]

My 2017 Sierra with the 5.3 rwd has been making this strange kind of a moaning sound intermittently and can be heard from inside and outside of the truck, any ideas or experience on helping me diagnose this?

 

[CamGTP]

Hard to say for sure.

 

It's not a fun task but you could remove the serp belt and the belt on the vacuum pump and start the engine to see if the noise is still there. Can't run the truck for a long time with no alternator and water pump working but if the noise completely stops, then it's one of those things on the belt system. Be it a pulley, water pump, vacuum pump etc etc.

[tlr_42]

Still does it with all belts off 

[mjm-1957]

We have a few of them with noise and it was one of the cooling fan motors. Unplug one at a time to see which one is making the noise.