Well, I bought my Moto Guzzi motorcycle from a Hungarian guy that has a Tdi shop in Madison. He works on everything, but he seems to specialize in these VWs. He has a buddy with an LTL wedge and an F350 and I think the guy brings him work. I saw Alabama plates on a Tdi in his shop. This mechanic says the engine in my '96 Passat is the holy grail of Tdi's. It's 10mpg better than my brother's Passat on the highway. It's slow, he says, but absolutely reliable and extremely efficient. Mine has around 310,000 miles on it and he scoffed. He was pointing to extra engines he had in his shop from, I assume, wrecked vehicles, and saying they had 500,000 plus, and were just getting broken in. Back in Hungary, they fix everything as new parts are hard to get. If you live near Madison, Wisconsin, take your car to him--any car. I saw the things he could do--very impressive ability.
The good things about my Passat are the mileage-40 in town and close to 60 on the highway. With an 18 gallon tank, you can go really, really far without refueling. It's a tight handling car with the mechanical bits really well built.Transmission and brakes and everything--brilliant.
Where it falls down is that the interior is rubbish. It's very spacious--NFL offensive lineman would have no problem riding in the back--and a couple dead ones would easily fit in the enormous trunk. But the interior door handles break off. Some mornings, the dash lights don't come on and I have to guess how fast I'm going. The door panels are pulling loose from the doors. The headliner is coming down. The seat fabric is whipped and it has seat covers. The power windows work intermittently. It's wonderful to drive, but very annoying to be in. It's like an '80s Chevy Citation inside, quality-wise. It's a nice place to sit, unlike to Citation, but everything you touch either breaks or doesn't work, like the Chevy.
I haven't driven it in 2 months. It's air conditioning compressor exploded last year doing $500 of damage to engine components. I fixed everything, putting an idler in place of the compressor, and drove it quite a bit last winter when I had to move kids in small numbers. This summer, I have mostly driven the E350 because the air works, or ridden a motorcycle when I didn't have anyone to haul.
Compared to the 6.2: the Tdi and 6.2 both use very simple rotary pumps. The 6.2 is indirect injection, which means the fuel is injected into a pre-combustion chamber (like a mother-in-law cabin) where is is swirled into a blast of air to further atomize it. It has very high compression--almost 22:1--and when it starts on fire in the pre chamber, the start of combustion throws everything into the main chamber to finish the job. The result is a cackly, loud engine. The Tdi is a direct injected engine, running a much lower compression, about 18:1, but similar injection pressure. The secret there, I think, is the pre-chamber was basically moved into the piston.
The 6.2 is loud--it sounds like the pistons are whacking the cylinder heads. It feels like the pistons are whacking the heads. Things shake loose.There's always something rattling. The high compression and the prechamber vomiting the partially burned mixture into the main chamber is why. The Kubota I had in a Bobcat was the same way. It would just smash everything around it.
Why is the TH400 my favorite tranny? I don't know. 25 years, 9 of them owned by me. Still lugging crap around with that nasty 6.2 hammering on it. Nasty 6.2 with 12psi of boost on it.