[B]STEP BY STEP AUDI TIMING CHAIN TENSIONER REPLACEMENT
I will start out by stating that you DO NOT HAVE TO REMOVE THE TIMING BELT TO REPLACE THE TIMING CHAIN TENSIONER. As so many guides including the Audi manual itself states that you have to essentially remove everything, timing belt, bumper, radiator, etc.. just to replace the timing chain tensioner. This is not the case at all and I have performed the repair multiple times in under an hour. The symptoms of a worn out timing chain tensioner are caused by one of two things: The first is the wearing out of the pads or deterioration of the high strength plastic they use. This will cause a consistent grinding, rough idle, low power, and the valves will not be correctly timed at all rpm's. The second type of failure is the hyd piston itself. If this fails it the timing chain will be fluctuating from completely compressed to complete extension. This will typically cause the timing chain to scrape against the valve cover. If you put your hand on the top of the valve cover you will easily be able to feel the metal on metal scraping. I will give a general walk through below:

Remove plastic Audi cover
Remove all wiring and coil packs from top of valve cover
Remove bolts that connect the metal pipe to the left side of the valve cover
Disconnect any air or vacuum lines making it very easy to remove the valve cover. When removing valve cover it must be lifted straight up off the studs and can not be angled.
After the valve cover is removed loosen all of the caps for both camshafts.
Remove the first 3 camshaft caps that are nearest to the timing chain tensioner
Be sure to keep tension on the timing belt to avoid any slipping
Remove the bolts that are holding the timing chain tensioner in place
Carefully angle both cams upward lifting the timing chain tensioner with them. This will take a little bit of time to finagle it out but it will come out without damaging any of the cam bearings as long as you take your time. You have to trust me though because the first one I removed this way seemed almost impossible until I stepped back and took a look, it reminds me of a the brain teasers you used to play with when you were young.
Once the old tensioner is removed slip the new one in and make sure it slides in level with the base it is bolted too because a high pressure oil line runs from the head into the tensioner itself.
When laying the cams back into place do not use force (pressure will be holding them up a small amount)
Once you have the bolts started for the cam caps SLOWLY start to tighten each cap a very small amount moving from one end to the other. It will damage the cams if you do not tighten each cap bit by bit to bring the camshaft to its normal position.
Now that the cam is lying in place and the tensioner bolts are tight you can proceed to torque the camshaft bolts to the proper torque depending on what DOHC engine you have.
Install the valve cover
Connect all vacuum lines and bolt the metal antifreeze line back to the valve cover
Install each coil pack and connect the corresponding harness (the coil packs are not cylinder specific so you can mix them up)
I would recommend an oil change before initial start up
Start it up and after about 10 seconds the tensioner will build pressure and be back to new!

You can give credit to the author below:
Audi Repair Blog (Audi Reparatur Blog): STEP BY STEP AUDI TIMING CHAIN TENSIONER REPLACEMENT

 

good reminder..! not exactly new news and even the audi dealers i have talked to say they dont follow the audi specs and leave the T belt on.... I just changed my tensioner about three weeks ago, bout 3 hours at the most (with a quick beer run in the middle) :P

 

Haha! And I thought I got away with something taking out the timing chain tensioner without removing the timing belt oh well.. I figured other people would try the same thing just because removing the timing belt the correct way is such a difficult thing to do in the first place. Thank you for the input though and in turn do you have any quick tricks I might be overlooking when it comes to the timing belt replacement without removing the front bumper and all the goodies that entails (specifically the B6 1.8T)

 

Just pull the bumper and open the core support. The 40-60 minutes you save by skipping that step will be consumed a couple times over when trying to see and find bolts and having to change sockets 4 times before you find the right size.