To inspect the viscous coupling, disconnect the battery by taking off its negative cable. Rock the fan with your hand to check if it has got too much bearing play. While cold, try to spin it by hand and make sure that it is rotating without restriction. If any problems with fluid leakage are noticed in the clutch, replace it. Reconnect the battery cable, warm up the engine, turn off the ignition switch and disconnect the negative battery cable again. When you can turn the fan blade by hand with no effort, replace the viscous clutch assembly. Depending on engine type and model year follow specific removal steps as shown below. Disconnect the negative cable and reservoir hose then remove the shroud if needed. After that take out fan/clutch assembly, inspect the blades for damage, and tighten properly on installation.