How to Change the Thermostat in a Cobaltby Zyon Silket
The thermostat in the Chevy Cobalt is located inside the water inlet housing, which bolts onto the bottom of the water pump. Because the housing is located low on the motor, you must remove the coolant from the radiator before you can proceed with removing the defective thermostat. This makes the job somewhat harder, but the task is not overly difficult to complete.
Place a drain pan under the petcock located on the bottom of the radiator. Open the petcock with a pair of pliers and drain the coolant from the radiator. Close the petcock, once drained.
Follow the lower radiator hose to the engine to locate the water inlet housing. The hose connects to the housing. Pry the hose clamp off with the pliers and then pull the hose off the housing.
Remove the two nuts that secure the water inlet housing to the studs on the water pump with a socket and ratchet. Pull the housing off the housing.
Take note of the triangle imprinted on the top of the thermostat. It rests between the two studs on the water pump. When you put the new thermostat into the water pump, place the triangle in the same position.
Pull the old thermostat out of the thermostat housing.
Place the O-ring gasket onto the new thermostat. Use the old thermostat as a guide for how this looks. The thermostat 0-ring comes with the new thermostat.
Place the new thermostat back into the water pump.
Place the water inlet housing back onto the water pump and tighten it in place, using the socket and ratchet.
Slide the radiator hose onto the water inlet housing and secure it with the radiator hose clamp.
Remove the radiator filler cap and place a funnel into the filler spout. Drain the radiator fluid back into the radiator and close the cap.
Items you will need
- Drain pan
- Socket set
- "Chevrolet Cobalt, Pontiac G5, Pontiac Pursuit Repair Manual 2005-2007"; Jay Storer, John H. Haynes; 2007
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