Viscous Fan Coupling - 28mm Thread - 35mm Nut Size. If your Crank Thread is the Smaller 24mm with a 32mm Nut you will need ETC1260 for 3.9 & 4.2 Petrol Engines with multiple belts. Landrover Petrol V8 Engines From 1994 With 1 Long Serpentine Belt (NOT P38 or Discovery 2).