[Vwdiesel] 100,000 miles

[William J Toensing]

Since I don't own a VW TDI, I can't really comment on how often you should change the timming belt. However, VW diesels & probably all diesels as well as many gas engine cars have what is called an "interference" engine. This means that if the timming belt, chain, or gears break, the valves could contact the pistons with costly consequences.
My daily driver, a 2001 Ford Focus ZX3 uses a timming belt & has an interference engine. I saw a Focus advertised with a little over 100,000 miles & a "new engine". She said she had the local Ford dealer change her timming belt at 70,000 miles & at around 80,000 or 85,000 miles, the new timming belt failed. Turns out, the dealer failed to replace the timming belt idler pulley & it seized, causing the "new" timming belt to break, hence the need for a new engine. When I heard this, I immediately had my Focus' timming belt changed. Ford recommends a Focus timming belt change every 100,000 miles (or maybe 125,000 miles, I will have to look in the owners manual). The old timming belt  still looked good, BUT the idler pulley bearing was loose & likely would have failed in 3,000 miles, the mechanic who changed the belt estimated.  I don't know about the TDI, but the timming belts on my Dasher & Quantum had a similar arrangement & I replaced their idler pulleys too.
Bill Toensing, Nevada City, CA