Loud chirp during start up 2016 GMC Yukon

[Congtoid]

I posted on the wrong forum, moving it here:

Installed mud flaps and changed the serpentine belt on my ‘16 Yukon, figured that would cure the problem “chirp” at startup. Whether it’s cold or hot, it does it. Anybody have an idea as to what it could be? Thanks.
+ I walnut blasted my intake valves about 2-3 weeks ago, would that have anything to do with the chirp?

I recorded this video today, around the 4 second mark you can hear a chirp for a split second before the engine turns on.

 

[Joseph Garcia]

Did you change the pulley tensioner assembly when you replaced the serpentine belt?

 

[Congtoid]

No I did not. Would you recommend changing it?

I think the noise is coming from this part, is this the water pump?

 

[Joseph Garcia]

It is a good idea to change the tension assemblies when you change the belt (both, if you have 2 belts and 2 tensioners). They are spring powered, and the spring weakens over time.

Take the serpentine belt off and start the engine briefly and see if the noise goes away.

 

[PPV_2018]

That’s the water pump pulley. Check for play on the pulley. It should be firm with no play at all. If indeed the noise is coming from there, the bearing may be failing for the pulley and it might be on its way out.

Also i agree with @Joseph Garcia that the tensioner should be changed when the belt is changed.. however I believe k2 only has one tensioner and 2 stretch belts if the same as my 2018.