The 5.2 and 5.9 magnums do not have a tensioner. There is an aftermarket one that can be added but it does nothing. If there was one factory, don't you think I would've seen it on mine!?!

 

Where I think people get confused is the the cam gear is labeled as a tensioner

 

Not from the factory, it's a field upgrade. When you install a new timing set, it goes on the left side of the block, as you face the engine, and has a pin in it. Once you get everything timed and are ready to reassemble, you pull the pin and it tightens the assembly up so there is no slack what so ever. This came out in the late 90's.