The 2.5-liter Audi AAT 2.5 TDI diesel engine was produced by the company from 1991 to 1997 and was installed only on two models of the concern: with an index of 100 or a similar A6 in the C4 body. This five-cylinder power unit is famous for its high reliability and long service life.
The EA381 series also includes: CN, AAS, AAT, 1T, AEL, AHD, BJK, BJM.
Specifications
| Production years | 1991-1997 |
| Displacement, cc | 2460 |
| Fuel system | direct injection |
| Power output, hp | 115 |
| Torque output, Nm | 265 |
| Cylinder block | cast iron R5 |
| Block head | aluminum 10v |
| Cylinder bore, mm | 81 |
| Piston stroke, mm | 95.5 |
| Compression ratio | 20.5 |
| Features | SOHC, intercooler |
| Hydraulic lifters | yes |
| Timing drive | belt |
| Phase regulator | no |
| Turbocharging | yes |
| Recommended engine oil | 5W-40 |
| Engine oil capacity, liter | 5.2 |
| Fuel type | diesel |
| Euro standards | EURO 2 |
| Fuel consumption, L/100 km (for Audi A6 1995) — city — highway — combined |
8.5 5.4 6.8 |
| Engine lifespan, km | ~550 000 |
The engine was installed on:
- Audi 100 C4 (4A) in 1991 – 1994;
- Audi A6 C4 (4A) in 1994 – 1997.
Disadvantages of the Audi AAT engine
- One of the most reliable diesel engines of its time rarely worries its owners;
- Most of the problems are associated with malfunctions of the Bosch VE37 electronic injection pump;
- The aluminum cylinder head is afraid of overheating, it quickly leads mating surfaces;
- Replacing a timing belt with rollers is expensive, but when it breaks, the valves always bend;
- At high mileage, the turbine, mass air flow sensor and hydraulic lifters may require replacement.
