The oil pump in a 2000 Nissan Altima is located in the engine's oil pan. The oil pump is responsible for circulating oil throughout the engine, and is driven by the engine's crankshaft.
To access the oil pump, you will need to:
1. Remove the oil pan from the engine.
2. Locate the oil pump, which is located at the bottom of the oil pan.
3. Remove the bolts that hold the oil pump in place.
4. Carefully remove the oil pump from the engine.
When reinstalling the oil pump, be sure to:
1. Use a new oil pump gasket.
2. Tighten the oil pump bolts to the specified torque.
3. Refill the engine with oil.
