How to Replace a Thermostat on a Nissan Altima

The thermostat used on the Nissan Altima bolts onto the intake of the water pump. This places the thermostat directly into the cooling system. It also makes the task of replacing the thermostat slightly more difficult because you have to access the thermostat from below the vehicle. When the thermostat stops working, your Altima could overheat, causing engine damage that could cost thousands to repair. This is a good reason not to put off replacing your thermostat.
Difficulty: Moderate
Instructions
Things You'll Need
Ramps
Clean drain pan
Pliers
Socket set
1

Drive your Nissan Altima onto a set of ramps and secure the vehicle by pulling the parking break. Allow the vehicle adequate time to cool off to avoid possible burns from coolant.
2

Place a clean drain pan under the drain valve on the radiator. Open the valve with the pliers and drain the coolant into the pan. Close the valve once the coolant drains.
3

Follow the radiator hose to where it connects to the thermostat housing on the water pump.
4

Remove the two nuts that secure the housing to the pump, using a socket. Pull the housing off the water pump.
5

Take note of the positioning of the thermostat inside the pump. The thermostat has an arrow on it. The arrow rests between the two studs that held the thermostat housing to the pump. When replacing the thermostat, place the arrow in the same position.
6

Pull the thermostat out of the water pump.
7

Place the new gasket on the new thermostat. The gasket fits around the metal flange in the center of the thermostat. Use the old thermostat as a visual aid.
8

Slide the new thermostat into the water pump. Make sure the arrow rests between the studs in the same position as the old thermostat.
9

Place the thermostat housing back on the water pump. Secure the housing in place with the two nuts previously removed.
10

Open the radiator cap. Pour the coolant from the drain pan back into the radiator through the filler spout. Tighten the radiator cap and close the hood. Back the Altima off the ramps.