The 2.5-liter V6 Alfa Romeo AR32405 engine, which was manufactured in Arese between 2000 and 2005, was exclusively fitted to sophisticated versions of the 156 model that were well-liked in the European market. The 166 sedan had another comparable power unit installed under its own index, AR36201.

The Busso V6 series includes: AR34102, AR32405, AR67301, AR16105.
Specifications
| Production years | 2000-2005 |
| Displacement, cc | 2492 |
| Fuel system | distributed injection |
| Power output, hp | 192 |
| Torque output, Nm | 218 |
| Cylinder block | aluminum V6 |
| Block head | aluminum 24v |
| Cylinder bore, mm | 88 |
| Piston stroke, mm | 68.3 |
| Compression ratio | 10.3 |
| Features | no |
| Hydraulic lifters | yes |
| Timing drive | belt |
| Phase regulator | no |
| Turbocharging | no |
| Recommended engine oil | 10W-40 |
| Engine oil capacity, liter | 6.4 |
| Fuel type | petrol |
| Euro standards | EURO 3 |
| Fuel consumption, L/100 km (for Alfa Romeo 156 2002) — city — highway — combined |
17.0 8.8 11.8 |
| Engine lifespan, km | ~280 000 |
| Weight, kg | 190 |
The engine was installed on:
- Alfa Romeo 156 (Type 932) in 2000 – 2005.
Disadvantages of the Alfa Romeo AR32405 engine
The majority of this motor’s issues are caused by suction through fractured pipes.
This results in airing the system, overheating, and floating engine speeds.
Frequently, a malfunctioning water pump or thermostat causes the engine to overheat.
The resources of hydraulic lifters and liners are significantly impacted by oil savings.
Every 60,000 kilometers, the timing belt must be replaced to prevent the valves from bending.
