Just had the timing belt replaced on my 60k mile, 2003 TDI PD130 Passat, a quoted price of £300 inc tensioer, relay roller, water pump and drive belts.
However, I got the customery phone call, " Oh dear, we've found a problem with your auxillary belt tensioner, they are £90 to replace".
There was a small amount of play (1.5 mm max) in one end of the hydraulic tensioner, and apparently this garage, an independant VW specialist have had several failures of late. The play allows fouling of the belt pulley and the hydraulic tensioner, the pulley seizes, and the belt comes off causing damage to the fan, ac belt, alternator pulley etc..
I couldn't argue, but has anyone had an experience of this?

Many thanks