Diagram reference number 11 in the image below:
" Fitment: 2007 NISSAN SENTRA - 4 door

Application Notes: O-Ring; Control Valve to Head

Category: Cooling

SubCategory: Thermostat, Gasket, and Housing

Position: General

Part Number: 210496N220


This is a Engine Coolant Outlet Gasket that fits the 2007 NISSAN SENTRA - 4 door with the MR20DE engine. The Engine Coolant Outlet Gasket is designed by NISSAN to be part of the Cooling-Thermostat, Gasket, and Housing. The Engine Coolant Outlet Gasket has a position on the vehicle of General. The 2007 NISSAN SENTRA Engine Coolant Outlet Gasket is a factory made NISSAN OEM part and it comes with a 12 month 12,000 mile warranty (parts only). Do not be fooled by an aftermarket NISSAN SENTRA Engine Coolant Outlet Gasket! Buy a factory NISSAN part and receive peace of mind!
This factory part has a part number of 210496N220.