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How to Change the Thermostat in a Nissan Altima

by Contributor

The Altima sets itself apart from the pack by offering sporty handling with ample, refined power as well as a comfortable, pleasant interior. The third generation Altima (2002 to 2006) is in demand by used-vehicle buyers. The following information details the installation of a new thermostat in those models.

Step 1

Drain the coolant from the radiator and store it in a proper container. Take the negative battery cable from the terminal.

Step 2

Disconnect the radiator lower hose from the [engine coolant]( inlet side. Take out the engine coolant inlet and the thermostat.

Step 3

Install the new thermostat with the entire circumference of the flange fitting securely inside the rubber ring. Make sure the jiggle valve is facing up with a deviation of the position plus/minus 10 degrees.

Step 4

Use Genuine RTV Silicone Sealant or an equivalent product when installing the temperature sensor for the engine coolant. Apply a mild detergent to the O-ring when setting the heater pipe into the housing.

Step 5

Refill the cooling system with the appropriate type and amount of coolant. Reconnect the battery ground.

Start the engine and allow it to run for several minutes. Check the system for coolant leaks.


  • The hoses slide onto fittings or connectors that grip the individual hose and hold it in place with a clamp. No special tools are required to remove or reconnect hoses. Label the hose and its connectors before separating.


  • Make sure the engine and radiator are completely cool before beginning this procedure.
  • Keep in mind that dogs and cats are attracted to and will drink coolant left in open containers or puddled on the floor and ingestion is often fatal. Drain coolant into a container that can be sealed. Reuse the coolant unless it is contaminated or old.

Items you will need

  • Mechanic's toolset, including a full socket set, wrenches and screwdrivers
  • Replacement thermostat, new or rebuilt
  • New gasket for thermostat

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