2007 Jaguar XJ6 LOCATION OF ITEMS BELOW

Vehicles with Diesel Engine
The diesel fuel filter is located in the engine compartment. Incorporated in to the fuel filter housing is a bimetallic valve which will start to close at 30 °C (86 °F) and will fully close at 50 °C (122 °F).
When the bimetallic valve is open, fuel is only allowed to pass through the fuel cooler in the engine vee, which aids warm up of the fuel at low temperatures. When the fuel temperature increases, the bimetallic valve closes, diverting fuel through the under-floor fuel cooler which then lowers the fuel temperature before returning the fuel back to the fuel filter.
The fuel filter has an air bleed return to the fuel tank which returns excess air and fuel back to the fuel tank.

Sump/Oil drain plug is located on the sump/oil pan.