dzywicki

I have a new to me 2008 A6 4.2. Got it in January and have been going through all the major areas to make sure things are good. I had replaced the coil connectors and that finally got rid of my intermittent misfires, replaced the rotors and pads, just got new tires. On Friday after work, I started the car to head home and heard this awful rattling sound. I turned off the AC and it was still there. Turned it off and took a look but didn't see anything wrong. Started it back up and the rattling was gone, but had the check engine and battery light on.
I liv3 pretty close to work so chanced it and drove home since the rattling had gone away. Once I got home, I checked again and saw that the serpentine belt was off. I pulled it out and saw a tear on the edge of the belt and figured the belt was worn and needed replaced. I also had two other jobs that had been putting off: 1- putting a snub mount back in, it was missing from the previous owner. An d 2 - checking the homelink transmitter that was working very intermittently. So, I decided to take the front off and get them all done.
Took about 1.5 hours to get the front end off and was easily able to find the homelink transmitter. Got some pics of the old one and will look for a used one on eBay. I did search for the part number and it's listed at $980 from various sources. Snub mount replacement was pretty easy with the front off. Then it was on to the belt. I wasn't sure what had caused the belt to come off so I started grabbing things. the tensioner was really loose. I pulled the first mounting bolt and noticed while I was backing out that it was bent. It came out after removing that one bolt. I saw 4 mounting holes on the bracket and figured out pretty quickly what the problem was. Then I recalled the bolt I had found in the belly pan the first time I took it off for an oil change. I made a test fit and realized that the second bolt was only grabbing 1-2 threads and must have fallen out.
Went to the auto store and found m6 1.0 50 mm. But....it wouldn't fit in the recessed mounting hole. A 1/2" drill bit fixed that problem. Got that mounted up (with some loctite). Had to use a pipe over the socket to get the tensioner all the way loose so I could get the belt on. The tensioner bolts are accessible without removing the front clip.
Wanted to pass this on in case anyone ever runs into this situation. Check those tensioner mount bolts when you have the belly pan off so you don't run into this problem.

And those 10mm nuts on the inner fender. See these two? These are for you 10mm inner fender nuts: