Timing belt

[Rocco]

Pkm told me to open engine every 10000 kms ,so it seems a good timing belt insurance

[mcandmar]

~100k miles is utter madness. Rubber breaks down with heat/age hence they need changed regularly, even a brand new belt has a best before date on it for that reason.

Newer vag cars i would do 60k without exception, i think Audi list 80k miles but i have had the pleasure of rebuilding a TT engine with 75k miles on it when the belt shred its teeth on the motorway. A £20 belt and a few hours work would have saved the owner a fortune.

[EspenW]

Problems are usually caused by seized pulleys/tensioners and/or oil contamination of the belt.
The strength of the belt comes from the internal fibers that are usually made from fiberglass or kevlar. These break down from use, ie mileage. The rubber in the teeth, however, can disintegrate from dryrot, and that is running environment/age related.

[EspenW]

1.8T's had massive problems with snapping belts. That was due to faulty tensioners.
Our B6 A4 1.8T has 120k km intervals. I replaced it at 100K km. Fairly easy job on the 1.8T, just place the entire front in the service position (moves it forward by approx 10cm)
The tensioner on that one started making noise at 50K km, was replaced by the dealer under warranty.

The interesting thing is that the impeller of the water pump came out in pieces, Audi still insists on using crappy plastic impellers. I got an aftermarket pump with metal impeller.