No sealant needed for the water pump o-ring. It will fit tightly in the groove in the pump and will stay in place. The drain cock for the radiator is easy to get to. The fan may come loose with an adjustable wrench. Seem like the nut portion of the fan clutch is about 2 inches or so wide so this shouldnt be a problem. May have to wedge a prybar something behind the water pump pulley to keep it from turning to get it loose. It WILL be tight. Right hand threads on the clutch BTW.