2015 2.7 Double Cab - whine/groan

Hello all.

New owner of a 2015 2.7 double cab. 49k miles. Very very good condition.
Noticed a slight groan/whine that varies as I accelerate and dissipates as I get to cruising speeds.
I also noticed its completely gone when I turn off the AC. Does not occur at all.

I have tried searching and best I can find is possible idler pulley?

Anyone have any other thoughts what it may be?

Thanks in advance.

 

Start with the tensioner pulley ($30 compared to $130 for a complete tensioner when it decides to fuse itself together) was the source of my whine. Good luck!

 

Anyway to check if its bad?

 

Pop the belt off and spin it

 

Common to fail with less than 50k? I assume I would be looking for rough spinning? I thought I had read about "wobble"?

Sorry for all the questions- appreciate the info

 

Yes this sounds like a belt tensioner issue.

The pulley should spin freely and smoothly without any wobble or hesitation. I'd replace all three and the belt while you're at it. Not a very difficult job really

 

Had my idler pulley replaced at 35,900 miles on my '15 2.7. Luckily it happened 100 miles before the warranty expired.

 

Sorry for the stupid question - is there a post on this forum that walks you through it? I am pretty mechanical and have no problem doing it but usually like to watch vids or tutorial to avoid costly missteps

Thanks again to all.

 

Not that I know of. I just did this last weekend actually so it's pretty fresh.

I removed the front grill and radiator to get more room, but I was also replacing the water pump and radiator hoses at the same time so I needed to drain the coolant anyways.

You will need a 10, 12, 14 mm socket. Helps immensely to have two sets of hands, but I suppose you could do it solo.
To remove the belt there is a 14mm bolt on the tensioner pulley. Take the belt off and it's basically just undoing the bolts that hold on the pulleys and replacing, putting it all back reverse order

 

Last question; best resource (or brand) for pulleys?

 

I got all my parts for this job from rockauto. Amazon sells kits for cheap too.

 

Wait now, let's back up the truck on the pulley thing. You said it "completely" goes away with AC turned off...that alone, would direct me to the AC compressor and/ or clutch.

 

I initially thought that as well.....but its all working ok.
At idle, with AC on, no groan/whine.
Its almost like a harmonic thing under acceleration (while driving).....as it gets going, it disappears.
If I have AC on and sit in park and accelerate, I dont hear a thing.

With AC off, nothing at all - driving, sitting idle etc.

To be honest, I thought it was torque converter.....as it seems to be building pressure and then dissapears.