Mercury 4L2Z-6600-A Oil Pump Assembly

To remove the oil pan, first take out the oil pick-up tube-to-main bearing cap nut and then the oil pump pick-up tube mounting bolts, along with the two bolts that detach the oil pick-up tube. Next, remove the oil pump mounting bolts and lower the oil pump assembly; if the pump is faulty or suspected to be faulty, install a new one instead of attempting repairs. The oil pump hex driveshaft will come out with the pump, so examine the ends for wear and replace it if either end is worn, as a broken shaft can cause serious engine damage. For installation, prime the oil pump by pouring clean oil into the pick-up and turning the pump shaft by hand. If the pump is separated from the pick-up tube, use a new gasket and securely tighten the bolts. When reinstalling the pump, ensure the oil pump driveshaft fits all the way into the pump without forcing it; if it doesn't align with the bottom of the camshaft synchronizer, turn the pump slightly and try again, noting that the end with the stop-clip goes up into the engine block. Finally, install the mounting bolts/nut and tighten them to the specified torque.

It is suggested that the oil pump be replaced whenever the engine is reconstructed or if the pump miles are high or if the pump is otherwise suspect. Start by doing away with the oil pan. When supporting the oil pump remove the bolt fixing the pump to the rear main bearing cap. Lower the pump and remove it, also take out the pump driveshaft. When a new oil pump is to be fitted, make sure that the pump driveshaft fits appropriately with that in the pump. Locate the pump in the vicinity of the engine so that it can be captured by the driveshaft; the hex in the upper side of the driveshaft must engage the lower side of the distributor or camshaft position sensor shaft; these components drive the oil pump and they must be compatible. Bolt the bracket to the surface and torque the mounting bolt to the recommended value. Last, the oil pan has to be refitted and oil has to be supplied and the installation process is to be done in the reverse order to the dismantling process.