VW/Audi 4.2 TDI Engine Specs, Problems, Reliability. The 4.2-liter V8 TDI diesel engine is based on the 4.0-liter variation. The first V8 TDI was installed in Audi A8 in 1999, and it was the 3.3-liter version. The 4.2-liter engine is the last generation of the V8 TDI series.
The engine has cast iron cylinder block with the exact same bore spacing 90 mm and 90 degrees V-shaped setup as the 4.0-liter version. The engine got forged steel crankshaft. The cylinder heads have the comparable design as 3.0 l V6 TDI heads. They are made of aluminum alloy, have four valves per cylinder, 2 camshafts, hydraulic tappets/lifters. The engine has single-row timing chains set up in the rear end of the engine. That makes very challenging to change them.
The V8 TDI has the Common Rail fuel injection system. That enables minimizing the fuel usage and emissions. For more power output, the engine was geared up with two last generation turbochargers Garrett GT17 (pressure has to do with 2.5 bars), one for each header.
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VW/Audi 4.2 TDI Engine Problems and Reliability
- The V8 4.2 TDI diesel engines are exceptional worrying reliability. Some of them had problems with the consumption manifold and throttle.
- All bearing of axes, rods, and levers inside were made of plastic until 2009, which wear out really rapidly (40-50,000 miles). As a result, reduced power and torque because of various spaces and skews. New ones changed this weak parts later on, and problems with them never ever occurred once again.
you must see more engine detail in here: Engine – US Cars News or you can see on wiki here
VW/Audi 4.2 TDI Engine Specs
| Manufacturer | Audi Hungaria Motor Kft |
| Production years | 2005-present day |
| Cylinder block material | Cast Iron |
| Cylinder head material | Aluminum |
| Fuel type | Diesel |
| Fuel system | Common rail |
| Configuration | V |
| Number of cylinders | 8 |
| Valves per cylinder | 4 |
| Valvetrain layout | DOHC |
| Bore, mm | 83.0 |
| Stroke, mm | 95.5 |
| Displacement, cc | 4134 |
| Type of internal combustion engine | Four-stroke, turbocharged |
| Compression Ratio | 16.4 |
| Power, hp | 320-349/3750-4200 |
| Torque, lb ft | 479-590/1600-3500 |
| Engine weight | – |
| Firing order | 1-5-4-8-6-3-7-2 |
| Engine oil weight | TITAN GT1 PRO C-3 5W-30 (XTL-Technology) |
| Engine oil capacity, liter | 11.5 |
| Oil change interval, mile | 10,000 |
| Applications | Audi A4, Audi Q7, Volkswagen Touareg, Volkswagen Marine TDI 350-8, Porsche Cayenne |
VW/Audi 4.2 TDI Engine Modifications
- BNV – 326 hp and 479 lb-ft version Audi D3 A8 4.2 TDI Quattro from July 2005.
- BTR – 326 hp and 561 lb-ft engine for Audi Q7 4.2 TDI.
- CEM – 349 hp and 590 lb-ft engine for Volkswagen Marine TDI 350-8.