[PLP]

look into kia tech info - free service (link below, use internet explorer only).
on the other hand - simply pull the belt and see which one (pulley) will react - tht one is tensioner.

 

[PLP]

That doesn't work, the tension pulley is not spring loaded. The pulleys on my '04 Sorentos (I have 2) aren't spring loaded either.

Well, in mine, V6 2.7 it is spring loaded.
I checked it again.

Anyway, you have a wrong picture.
Here is the right one (this is for 2.7).
And description: the drive belt(A), the idler(B) and the tensioner(C).

And guys - since none of you spent time to fill out profile, I have no idea if you are talking about I4 or V6...


EDIT:
only picture suggest you are talking about I4. So, the idler is the small one closest to PS pump, while tensioner is that one below, where the belt makes 180 degree turn. Do not mistake it with the idler next to alternator.
Or in other words. The next picture on kia tech info explains what is what.

 

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...Sorry I didn't bother to fill out my profile information but ....

It is always much more helpful to have the info in profile...

Well thanks for the help, but I do not have the wrong picture as I have the Rondo with I4...

Yes, you do. In terms of symbols (letters). If you looked on the next picture (on kia tech info) jsut below that one you posted (in TB section) you would find clear description what is what.
And I did repeat that above. I explained which one is tensioner.

 

[PLP]

here it is, just in case you could not find it.
7. Remove the idler pulley(A).
8. Remove the drive belt tensioner(B).

 

[PLP]

I can't say about I4, but in V6 I put a wrench on the tensioner, pull it hard (it is STRONG spring) to release the belt, move the belt aside, and release the tensioner. Enough room to do that.

And I do not think you need to remove the pulleys to change the belt...