The diesel is a common rail unit designed and produced by Volvo and will replace the Audi-sourced 2.5-litre currently available in the S80 and V70. Volvo is pitching the car against diesel cars in the Audi, BMW and Mercedes-Benz ranges. The first cars will reach UK showrooms at the end of this month before going on sale in October, and the company is hoping the car will help reach its ambitious sales targets over the next four years.
Volvo will also be launching a 130bhp version of the engine elsewhere in Europe, but wants to make its mark in the UK premium sector as a manufacturer of high-performance diesels.
Volvo is proud of the fact that its 2.4-litre five-cylinder uses the second-generation common rail fuel injection system from Bosch, which means higher injection pressures, better power and torque and lower emissions. The D5 engines also use cooled exhaust gas recirculation to further reduce emissions of nitrogen oxide. However, the important emissions for fleets are the carbon dioxide emissions, and both the S60 and S80 will fall into the lowest company car tax band for diesels under the first year of the new emissions regime from April 2002. The S60 will retain its 18% status during the second year.
I first took to the road in the S60 diesel, and the oil burner made its presence felt with a remote 'clatter' at start-up from cold. However, the engine is near silent inside the car at idle and remains quiet on the move. When you rev the S60, the engine has a distinctive five-cylinder snarl. This is the only characteristic obvious from the engine's sound - the fact that it is a diesel is far less obvious. In terms of refinement, the D5 goes to the top of the premium segment. There is little of the booming quality found in the four-cylinder units from BMW, Mercedes and Audi.
It is also quieter than the five-cylinder 2.7 litre CDI found in the Mercedes C-class. The only unit in this class which provides more refinement and better sound insulation is the BMW 3.0-litre diesel found in the 3-series and 5-series.
The D5 has plenty of torque, although in the S60 it can't match the BMW 330d or Mercedes C270 CDI for performance. However, it is significantly faster than its less powerful rivals and will accelerate from 30-75mph in less than 10 seconds, closer to those at the high-performance end of the diesel sector than the higher-volume engines.
The S60 is among the class-leaders in terms of handling and ride, and the D5's readily available pulling power and sweet steering allows it to slingshot out of corners with breathtaking ease.
Our test car was fitted with 17-inch alloy wheels and wide tyres which I suspect contributed to its high level of road noise on abrasive surfaces. However, it is remarkable that when driving a diesel the engine noise was not a factor. The S60 is comfortable and well-built, the only cause for complaint being a stiff gearchange which needs a firm and steady hand.
The S80 feels larger than the S60 and is one of the largest cars in its class shaming rivals like the BMW 5-series when it comes to interior space.
It seems even more has been done to disguise engine vibration and noise being transferred to the cabin. The S80 offers a relaxed environment and the effortless torque of the D5 engine gently pushes the saloon along at low revs, but will surge forward when needed. The S80 D5 SE is priced a little lower than the 155bhp SE version of the Audi A6 2.5 V6 TDI and more than £1,000 lower than the SE version of the BMW 525d which has identical power.
The D5 engine is an impressive diesel, providing the right balance of power and refinement for the premium sector. The engine has more torque than Volvo's 250bhp turbo-charged T5 unit but with fuel consumption ranging from 44.1 to 47.1mpg, depending on the model, the D5 will have broad appeal for those who want a premium car with both performance and economy.