623k
While only having 144k so far on my 03 Jetta TDI, prior to this car, I had a 5 speed, 89 Jetta Diesel, (pre-TDI) which lasted 623,000 on its original, unrebuilt engine until it was totaled in a wreck in 2002.
The engine was a 1.6L, and didn't have the computer like the TDI does, however I'd say that it was about 90% the same as a modern TDI engine.
My father drove it the first 575k or so, using it in a sales route for years, before giving it to me after he had no bites trying to sell it for $500.
5th gear wore out at 425k, and a transmission was unbolted from a car behind the mechanic's shop, and installed in this Jetta.
Somewhere I have the paperwork showing all the costs involved, including going through 16 sets of Michelin tires, about 125 oil changes, A few sets of glowplugs, 1 clutch, 1 transmission, an oil pump at 615,000, more than 1200 tanks of fuel, (gheesh-- is that even possible?) several sets of brakes, and a set of coils/shocks, but suprisingly few other unexpected repairs other than normal routine maintenance. Dad even kept a tank-by-tank record of mileage and mpgs. Toward the end of its life it had dropped from 46-47 mpg, to about 35 or so.
The car was a GL (base model) with wind-up windows, and no frills. By the time he gave it to me, the front bumper was being partially supported by nylon weed-eater string, the left rear window would slip down about 1/8th of in an inch but could easily be cranked by reaching back from the driver's seat to keep the whistling noise away. Mechanicly, at 615,000 it was decent, but the oil pressure light had just started flickering which I figured was either the oil pump or engine bearings. I was going to try to get it to 650,000 or so before I replaced/rebuilt the engine.
At the time of it's 'unfortunate incident' when it met a Buick corner to corner at about 35 mph, it didnt leak oil, but seemed to developing a smoke issue, again probably due to a developing compression issue.
So-- I'd say that with proper care most people can expect 300k easily. By slowing down a bit, 450-500 k can be attained, and if you don't abuse the car, even 6-700k is possible. The more highway miles one drives, the better. Most people just cant keep a car that long without thinking they need something new.
Btw--Dad's just taken mom's 2000 Jetta TDI recently as his "new" car, and for her b-day, they bought a 2006 Pkg 2 TDI Jetta.
Other notable diesels in the family:
79 Rabbit Diesel 373,000 (Totaled Dec 1988) Dad's
1989 Jetta Diesel 623,000 Dad/ me (totaled 2002)
1983 Rabbit Diesel 400,000 (My car in highschool-- sold when I was 30) Odometer was broken for last 2 years I owned it and showed 372,000
2000 Jetta TDI mom/dad-- unknown mileage-- daily driver
2006 Jetta TDI mom 8,000 +/-
2003 Jetta TDI-- me. 143,000.