The source of the problem is a vibration from the 3.0-litre, common-rail Isuzu power unit's turbocharger which generates a resonance amplified through the Saab's subframe.
Engineers developing the Vauxhall Signum and Vectra models, due to use the same engine later this year, are co-operating with Saab counterparts after countering what one technician described as "vibration and buzzing" by tuning hydraulic engine mountings.
The V6 TiD accounts for around 10 per cent of 9-5 sales, with about half going to the corporate fleet business. Linear, Arc and Vector model derivatives with the V6 diesel had prices slashed by £1400 in October last year. Saab dressed the cuts as an initiative to help reduce company car tax liability.