Strange whine on cold start

I have noticed recently when starting my truck after sitting all night that I sometimes get a “hiss” / whining sound in the first 10 seconds of it starting. Only happens once and then doesn’t seem to happen again the rest of the day. Sometimes it doesn’t even make the sound, but it’s been happening a lot lately. You can hear it in the video attached towards the end.

https://streamable.com/np0yn

 

Guess it's more of a whine than a hiss. Sounds like maybe it could be a belt going bad? Thought maybe it was because I had AC or Heat on, not sure though. Is a quick noise then doesn't happen for the rest of the day? Any ideas?

 

I’m not hearing anything abnormal. Just the smog pump? A belt noise will be high pitched squeal. I currently have that I can try and record it for you.

also our trucks only have the 1 belt so it would squeal regardless I believe.

 

I saw someone mention the smog pump in a different thread when I was searching around, is that what you are hearing at the end of the video? I apologize its not the best video / sound quality. Is there a reason I don't hear it some days and have just now started noticing it?

 

Your '06 doesn't have a smog pump.

 

only 2012+ v6 trucks got SAIS (smog pump)

 

Well there ya go, so it's something else making that noise

 

Disregard that then...
yeah I’m just not hearing anything weird in the video. If it is the belt, it’ll get worse and then it’ll be obvious.

 

I'll go out and start my truck soon and see if I can get a better video of it. Of course it probably won't make the sound today when I am trying to diagnose

 

Yeah my belt only squeals on first start up, a few times a week.

 

Is it a long squeal, or is it just a brief squeal? The noise I hear is like a 1 second noise, but doesn't really sound like a squeal. It's hard to describe a noise, so hopefully I can get a better video of it.

 

Just started it up and it made the noise but super faint. Guess I will stop worrying about it for time being, doesn't seem to be anything serious.

 

Of course I went to record mine this morning and it didn’t squeal.... lol

 

I suspect what you are hearing is the ABS system charging up. My '05 makes a kind of "whooomp" sound right after starting in the morning, it's totally normal.

Post number 5: https://www.tacomaworld.com/threads/strange-noise-at-startup.81571/

 

Tell her to wait inside until its warmed up.....