How to Replace the Water Pump in a Pontiac Bonneville

The water pump is the heart of the Pontiac Bonneville's cooling system, circulating the coolant. Serious damage can be done to the engine of your Pontiac Bonneville by not changing out a faulty water pump.

Things You'll Need

  • Drain pan
  • Wrench set
  • Coolant
  • Sealer

3.8L VIN 1 Bonneville Engine

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

  • Support your vehicle with a jack under the car or with another engine support fixture.

  • Disconnect the negative battery cable and remove the air-conditioning compressor splash shield along with the supercharger with the accessory drive belts.

  • Remove the coil pack, if applicable, the front engine mount with the bracket, the supercharger belt tensioner, the power-steering pump and the idler pulley.

  • Loosen and remove the bolts attached to the water pump and the water pump pulley. Remove these two items from the engine.

  • Install the new water pump, placing a bit of bead sealer around the outside edge of the pump. Also attach a new gasket to the water pump.

  • Tighten the long water pump bolts to 22 foot pounds (30 Nm), and the short water pump bolts to 11 foot pounds (15 Nm).

  • Attach the water pump pulley, tightening the bolts to 115 inch pounds (13 Nm).

  • Reattach the engine mount bracket, tightening the nut that is positioned the closest to the air-conditioning compressor to 33 foot pounds (45 Nm) and all others to 58 foot pounds (78 Nm).

  • Reinstall the idler pulley, tightening the bolts to 37 foot pounds, the power-steering pump, tightening the bolts to 20 foot pounds (27 Nm), the front engine mount, tightening the bolts to 58 foot pounds (78 Nm), the Supercharger belt tensioner, tightening the bolts to 37 foot pounds (50 Nm) and the ignition coil pack assembly, tightening the nuts to 72 inch pounds (8 Nm).

  • Reattach all other components in the order they were removed and reattach the negative battery cable. Refill the cooling system and check for leaks.

3.8L VIN K Bonneville Engine

  • Place a drain pan underneath the radiator. When the engine is cool, drain the cooling system from the radiator into the pan and disconnect the negative battery cable.

  • Remove the accessory drive belt and disconnect the coolant hoses from the water pump.

  • Loosen and remove the water pump pulley bolts and remove the pulley. Align the bolt head of the long bolt up with the hole in the frame rail to remove it.

  • Remove the water pump bolts and the water pump.

  • Squeeze some sealer around the outer edge of the water pump and install the pump with a new gasket into the engine, tightening the long bolts to 22 foot pounds (30 Nm) and the short bolts to 11 foot pounds (15 Nm).

  • Reinstall the water pump pulley, tightening the bolts to 115 inch pounds(13 Nm) and reattach all other components in the reverse order in which they were removed.

  • Refill the cooling system and reattach the negative battery cables. Start the engine and check for leaks when the engine reaches normal operating temperatures.

4.6L Bonneville Engine

  • Place a drain pan underneath the radiator. When the engine is cool, drain the cooling system from the radiator into the pan and disconnect the negative battery cable.

  • Take out the upper filler panel, the secondary air-injection control valve, the air cleaner assembly, the oil level indicator tube nut, the water pump belt shield fasteners along with the shield and the water pump drive belt.

  • Remove the thermostat housing from the radiator outlet hose and take out the water pump cover bolts along with the cover.

  • Take the heater return hose out of the engine, along with the water housing crossover support plate.

  • Remove the water pump locking ears and to disconnect the housing from the water pump. Use tool Part Number J 388 16-A to do this.

  • Remove the support plate that is on the water-housing crossover and remove the seal.

  • Loosen and remove the water pump bolts and take out the pump.

  • Replace the seal to the recessed part of the water crossover.

  • Insert all components in the reverse order in which they were removed. Tighten the water pump bolts to 74 foot pounds (100 Nm), the water pump cover bolts to 89 inch pounds (10 Nm), and the water pump shield fastener to 98 inch pounds (10 Nm).

  • Refill the cooling system and reattach the negative battery cables. Start the engine and check for leaks when the engine reaches normal operating temperatures.