Every 30 000 miles make sure you change in Jaguar S-Type timing belt. For 2.7 motor in S-Type special size of timing parts are needed. Wise decision is to buy Jaguar’s factory timing belt for S-Type 2.7 to service. The accessory should have 195 teeth and be of 29 mm width. Quite usual and ordinary belts were used in 2008 cars with engine code AJD.
In any case go to other than 29 mm wide belt for DT17(AJD-) motor code. Actually, there are plenty of analog parts for Jaguar S-Type with 2.7 engine. So, make sure you buy for 2005 Jaguar S-Type quality materials only.