Produced between 2003 and 2010, the 6.0-liter 12-cylinder Audi BHT A8 W12 engine was mounted in the rear of the D3 on premium A8 sedan trim levels, including the extended A8L. This model also had additional motor modifications installed under the BTE and BSB indices.
The EA398 series includes: BHT, BRN, CEJA, BDN.
Specifications
| Production years | 2003-2010 |
| Displacement, cc | 5998 |
| Fuel system | distributed injection |
| Power output, hp | 450 |
| Torque output, Nm | 580 |
| Cylinder block | aluminum W12 |
| Block head | aluminum 48v |
| Cylinder bore, mm | 84 |
| Piston stroke, mm | 90.3 |
| Compression ratio | 10.75 |
| Features | no |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | on all shafts |
| Turbocharging | no |
| Recommended engine oil | 5W-30 |
| Engine oil capacity, liter | 12.5 |
| Fuel type | petrol |
| Euro standards | EURO 4 |
| Fuel consumption, L/100 km (for Audi A8L 2005) — city — highway — combined |
20.4 10.8 14.7 |
| Engine lifespan, km | ~240 000 |
The engine was installed on:
- Audi A8 D3 (4E) in 2003 – 2010.
Disadvantages of the Audi BHT engine
This motor is extremely concerned about overheating, so keep a close eye on the cooling system;
Scoring in the cylinders is caused by low-quality oil and frequent overheating;
A significant amount of oil is consumed as soon as raised cylinders start to knock;
The liners will rotate fairly quickly if the oil pressure drop is missed;
The timing chain drive has a finite supply, and the engine must be removed in order to replace it.