Hey guys--

I just replaced both my serpentine belt and my AC belt in my '00 A4 1.8t, and my AC belt is now too loose and squeals like a banshee. I've been searching around and saw that you can adjust the tension on it, but haven't been able to find an explanation or diagram of how to do so, ideally from underneath the car (I replaced the belts without pulling anything off other than the skid plate). Can anyone point me in the right direction?

Thanks!

 

The belt rides three pulleys - crank, AC, and the small one is the tensioning pulley. there are bolts above it that you loosen to slide it downward to apply tension to the belt. Then tighten the bolts to lock it in place.

 

On the tensioner itself there is a hex-shaped protrusion which is what you use to tension it:
Audi B5 A4 FWD 1.8T > Search > Belt Tensioner > ES#277714 A/C Compressor Belt Tensioner/Roller Assembly - 058260511
The service manual says to use a torque wrench on this hex (I think it takes a 16 or 17mm socket) and torque it to 30 N-m. The hex bolts get torqued to 23 N-m, and I believe take a 6mm hex (maybe a 5mm).

My AC belt tensioner was making a ton of noise, so I had to replace it. Getting the proper tension on that thing and then tightening the bolts is definitely easier said than done when your car is NOT in service position...

 

Got it (I think).. I was able to loosen the 6mm bolts and swing the tensioner down a little, and the squeaking is gone. The belt still seems a little loose, but I'm not going to touch it again unless I need to.

Thanks for your help, guys, I really appreciate it.