What’s causing this rumble & growling?

Hello everyone, this issue is on a 2007 TRD V6 4WD with 195K miles. I noticed that when after first start up in the morning or when I’m in park, i get get a rumble and growl thats very loud in the cabin and the sound is the strongest from the front of the engine. This happens when i have the AC on, and goes away when I turn it off or when the engine has a chance to warm up a few min, it also goes away when i start driving. I bought this truck used last week, and i put new tires on, new brakes, rear diff fluid, spark plugs. From my search it could be an AC issue even though there’s es no other sound or It could idler pulley? Thougts?

 

For fun I’d change out the tensioner pulley for $30, now instead of waiting and it exploding and fusing the pulley to the tensioner forcing you to buy the entire $130 tensioner then change the idlers until the sound goes away. Good luck! Edit: and maybe a new belt

 

This sound wasn't apparent during your pre-purchase inspection?

Have you tried pinning it down with an automotive stethoscope?

 

This issue is most notable after being in parked and AC running for a few minutes. I only checked the AC during the test drive to make sure it works which, i don’t get this rumble while driving.

 

I would start with a new serpentine belt and then go from there.

 

Figuring out the source of the noise, before throwing parts at it, is your best bet. 2nd on the mechanic's stethoscope.

 

Well, it's not what I was expecting. I took the truck in for an alignment, after replacing my struts/shocks (dropping the LCA method), and mention the noise to them. Turns out, the y pipe / mid area from the exhaust was rubbing against the body of the truck. The previous own must have ran over something and pushed the exhaust up causing the rub. They manage to make adjustment to the exhaust and the noise is gone.

 

My truck roars to life in the morning then chills out. It'll still roar when taking off when it's cold at lights, stop signs, etc. Pretty much goes away when it's warmed up.

I believe it's coming from the fan clutch.

Edit: of course I post this then see the culprit was the Y pipe....