hey all,

new here so bare with me.
I have a 2015 Silverado 1500. about 132,000 miles. have had zero issues and truck has ran great.
Recently it started to sputter a bit and figured new plugs were the fix so had those changed. a few days later i noticed it was still sputtering. the dealership that did the work noticed 1 of the plugs wasn't gapped correctly, so they fixed it. (this was Friday 9/15)
Yesterday I noticed this sort of knocking noise (ill try and upload the video). Have no idea what it is. I'm not too mechanical. so any thoughts or advice would be helpful.
Up and til now its ran great.
any thoughts here?
Thanks in advance

 

try removing the serpentine belt and see if the noise goes away

 

UPDATE:
took it to the Chevy dealer that usually does some of my work. it was the water pump. Has been replaced and sound went away. Truck seems to be running perfectly fine now.