Source: NissanHelp
1. Remove undercover.
2. Drain coolant from radiator.
Open radiator drain plug at the bottom of radiator and remove the radiator filler cap.
3. Remove Drive Belts
Refer To :Drive Belts Removal Procedure
4. Remove water drain plug on water pump side of the engine.
5. Remove right-hand side engine cover.
6. Remove coolant reservoir.
7. Disconnect lower radiator hose.
8. Disconnect oil cooler line.
9. Remove engine coolant inlet and thermostat assembly.
Note: Do not disassemble engine coolant inlet and thermostat
10. Install in reverse order.