It seems like a fairly straightforward job, but I don't "get" how the tensioner works.
1. Is it really necessary to replace the tensioner?
2. Is the tensioner pre-set, with a spring, or does it need to be tensioned to a torque spec?
3. It seems like the easy way to get at it is by removing the passenger side wheel and the plastic cover in the wheel well, but I see (in videos) people getting at it from the top with what looks like a super-long box wrench.
Every other belt I've replaced (on other cars), there has been some kind of locking bolt, and a range of adjustment. Help me unlock the mysteries of the tensioner!

 

Year? Engine?

 

2016 le 2.5l

 

1) No. Inspect it for damage and check it is free to rotate and still applies tension.

2) Preset.

3) See video.

https://www.google.com/search?client...0wkvYHKTs,st:0

 

Link for videodoesn't work

 

replacing 2AR-FE serpentine belt 2016 - Google Search

 

Easier than I thought! I could easily reach the tensioner with a wrench from the top. The "bolt" to turn is easy to spot, because it isn't really a bolt, its a bolt head cast in the tensioner. Some tips for anyone reading this
post:
1. Draw a picture of the route the belt takes. By Rule of Thumb the un-grooved back of the belt only touches the tensioner and an idler wheel.
2. Do remove the passenger side wheel and the plastic splash guard/cover- it makes it much easier to access the belt.