How to Replace the Water Pump in a Chevy Cobalt

The water pump is the heart of the Chevy Cobalt's cooling system, circulating the coolant. A faulty water pump can cause some serious damage to the engine of your Chevrolet Cobalt. Make sure to change out a bad water pump.

Difficulty: Challenging

Instructions

2.0L Cobalt Engine

1. Place a drain pan underneath the radiator. When the engine is cool, drain the cooling system from the radiator into a pan.

2. Remove the oxygen sensor clip and the thermostat.

3. Loosen and remove the retaining bolts to the water feed pipe and remove the water feed pipe and thermostat housing, twisting the water feed pipe to remove it from the water pump cover.

4. Take the retaining bolts off the water pump and remove the water pump assembly. Make sure that you take off the bolt that goes in through the front of the engine block so it can be removed.

5. Install the new water pump assembly, tightening the bolts to 18 foot pounds (25 Nm).

6. Put some sealant (P/N 12378521) on the water pump drain plug before installing it and tighten the water pump drain plug to 15 foot pounds (20Nm).

7. Lubricate the water feed tube o-ring with some anti-freeze and then install the water feed tube. Make sure to twist and push the tube toward the water pump when installing it, taking extra care not to damage the o-ring.

8. Tighten the thermostat bolts to 89 inch pounds (10 Nm) when installing the thermostat. Also reinstall the thermostat housing cap with its bolts.

2.2L Cobalt Engine

9. Remove exhaust manifold if your Chevrolet Cobalt has an automatic transmission, and then the cooling system from the radiator into a pan.

10. Raise the vehicle, making sure to support it securely. Take off the right front tire with the wheel and the front fender liner.

11. Take off the access plate from the water pump sprocket on the timing cover. Install tool J 43651 or something similar to the water pump sprocket. Secure the tool with access plate bolts.

12. Take off the bolts to the water pump in the following order: the bolt that holds the pump to the engine block first, then the bolt that holds the water pump to the front cover.

13. Remove the feed pipe, which holds the water pump to the thermostat housing. Then take off the two bolts which hold the engine block to the water pump.

14. Remove the water pump and then install the new pump, after using the threaded stud in the hub to line up the hub to the water pump sprocket. Tighten the 2 bolts that hold the pump to the engine block to 15 foot pounds (20 Nm).

15. Reinstall all components in reverse order, tightening the 2 bolts that secure the water pump sprocket to the pump and the last bolt to 62-inch lbs (7 Nm). Also tighten the bolts that hold the timing cover to the access plate to 18 foot pounds (10 Nm).

16. Refill the cooling system, start the car and check for leaks when the engine reaches normal operating temperature.

Tips & Warnings

• Loud noises coming from the cooling system in your Chevrolet Cobalt could be a sign that your water pump needs replacing. A leak in the coolant may also be an indicator.
• Never attempt to drain the radiator when the engine in your Chevrolet Cobalt is hot. The steam and the hot coolant within the radiator can cause serious burns.