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.
EA381 family: 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:
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.
Frequently asked questions about the Audi AAT
How much power does the Audi AAT make?
The Audi AAT develops 115 hp and 265 Nm of torque.
How much oil does the Audi AAT take and which one?
Engine oil capacity: 5.2 liters. Recommended oil: 5W-40.
Does the Audi AAT have a timing belt or chain?
The Audi AAT uses a timing belt.
Is the Audi AAT turbocharged?
Yes, the Audi AAT is turbocharged.
Does the Audi AAT need valve clearance adjustment?
No, the Audi AAT has hydraulic lifters, so the valve clearances do not need to be adjusted.
How long does the Audi AAT last?
The typical lifespan of the Audi AAT is ~550 000 km with proper maintenance.
What is the fuel consumption of the Audi AAT?
Audi A6 1995: city 8.5, highway 5.4, combined 6.8 L/100 km.
What cars was the Audi AAT installed on?
Audi 100 C4 (4A) in 1991 - 1994; Audi A6 C4 (4A) in 1994 - 1997.
What are the common problems of the Audi AAT?
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. All known problems.
