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How to Change Water Pump in Pontiac Cars

by Contributing Writer; Updated June 12, 2017

The Pontiac car is a compact vehicle, so a number of parts and components are installed within close proximity. The water pump on the Pontiac car is connected to the thermostat housing, so you must work with both of these parts to replace the water pump. Failure to replace a malfunctioning water pump puts the engine at risk of overheating, because it won't always receive the proper amount of coolant.

Under The Hood:

 How to Change Water Pump in a 1998 Pontiac Sunfire

Slide the drain pan under the radiator petcock. Open the petcock and allow the antifreeze mixture into the drain pan. Close the petcock. Loosen the water pump pulley bolts, but do not remove them.

Loosen the belt tensioners on the accessory drive belts. Depending on the engine, you might have a serpentine belt and one or more V-belts, or you may have one serpentine belt. The serpentine belt uses a spring-loaded tensioner to keep it tight---push the tensioner away from the belt, using a socket, then lift the belt off the pulleys. For V-belts, loosen the adjusting bolt in the slider brackets and push the accessory (alternator, power steering pump) toward the engine, then lift the loose belt off the pulleys.

Unplug the wiring harness on the back of the alternator. Remove the main power wire from the back of the alternator with the appropriate wrench. Put the nut back onto the stud, so you don't lose it. Remove the alternator retaining bolts, alternator and alternator bracket with the appropriate socket.

Remove the water pump pulley bolts, then remove the pulley. Remove the water pump mounting bolts with the appropriate socket, then remove the water pump with from the engine. Clean the mounting surface on the engine with a screwdriver and a rag.

Line the water pump-mounting surface with a thin layer of RTV silicone onto the water pump. Place the gasket on the water pump and press it into the silicone. Install the water pump and tighten the retaining bolts to 19 foot-pounds of torque.

Reinstall the alternator bracket and alternator. Plug in the electrical connector on the water pump, then install the power wire. Tighten the nut for the power wire firmly. Reinstall the accessory drive belts. Refill the radiator.

Items you will need

  • Drain pan

  • Set of wrenches

  • Set of sockets

  • Screwdriver

  • Rags

  • RTV silicone

  • Torque wrench

 How to Replace the Water Pump in a Pontiac Bonneville

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.

Items you will need

  • Drain pan

  • Wrench set

  • Coolant

  • Sealer

 How to Replace the Water Pump in a 2006 Pontiac G6

Removal

Loosen the drivebelt tensioner using a 3/8-inch drive ratchet on the tensioner hole. Note the routing path of the drivebelt so it can be put back on appropriately. Remove the drivebelt.

Open the cap on the coolant expansion tank in the engine compartment. Open the drain valve, and drain the coolant into a large container.

Disconnect the electrical connector for the ECT sensor. Unscrew and remove the sensor from the thermostat housing using a deep socket, extension and ratchet.

Detach any harnesses connected to the thermostat housing. Disconnect the outlet hose at the expansion tank. Disconnect the radiator hose at the thermostat housing cover. Most of the hoses require the use pliers on the hose clamps to remove them.

Remove the three bolts on the exhaust manifold heat shield with a wrench. Remove the exhaust manifold heat shield.

Detach the heater hoses from the thermostat housing at their hose clamps. Unbolt the housing with your wrench. Twist the housing away from the water pump to remove it and the water pipe. Separate the pipe from the housing.

Raise the car's front end and support it on jack stands. Remove the right front wheel. Unbolt and remove the fender splash shield with your wrench.

Unbolt and remove the water pump's access cover, located to the left of the drivebelt tensioner.

Connect a holding tool (the exact tool is named J-43651 at auto service departments) to the water pump sprocket, and make sure the sprocket can't move.

Remove the bolts connecting the pump to the sprocket with a wrench. Remove the bolts connecting the pump to the engine block using your wrench. Remove the pump. You may need to tap it with a soft-face hammer to loosen it.

Installation

Clean the bolt threads and bolt holes. Clean off all traces of gasket material from the sealing surface using a gasket scraper and acetone.

Insert a threaded stud into the pump flange to use as a guide pin. Install the new water pump. Install and tighten the bolts to the engine block with a wrench. Remove your guide pin. Install and tighten the bolts to the sprocket with a wrench.

Reinstall the water pump cover with its bolts and your wrench.

Lubricate the water pipe's seal lightly with silicon gel before connecting it to the pump. Reconnect the thermostat housing and water pipe.

Reconnect the fender splash shield and the wheel. Lower the car off the jack stands.

Reconnect the exhaust manifold heat shield.

Wrap the ECT connector's threads with Teflon tape. Connect the radiator hose, ECT connector and all harnesses to the thermostat cover.

Refill the engine coolant tank, using a fresh mix of water and coolant if the used coolant is contaminated.

Reconnect the drivebelt using the ratchet on the tensioner, making sure it follows the same path as before.

Items you will need

  • 3/8-inch drivebelt ratchet

  • Large container

  • Ratchet with extension

  • Deep socket

  • Wrench

  • Pliers

  • Floor jack

  • Jack stands

  • Tool J-43651

  • Soft face hammer

  • Gasket scraper

  • Rag

  • Acetone

  • Threaded stud

  • Silicon gel

  • Teflon tape

  • Water

  • Engine coolant

 How to Replace the Water Pump in a Pontiac Grand Am

2.2L Grand Am Engine

Disconnect the negative battery cables before you begin.

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

Elevate the vehicle and remove the right front wheel, the splash shield, the water pump sprocket access plate and remove the exhaust manifold if your vehicle has an n automatic transaxle.

Use the water pump sprocket holding tool (Tool Part Number J 43651) and attach it to the sprocket with access plate bolts, securing the tool to the front cover of the engine.

Remove the following bolts to remove the water pump: the three bolts attaching the pump to the engine block, the bolt to the engine front cover, the bolts to the sprocket and the bolt attaching the thermostat housing to the pump.

Remove the old pump and install the new one, aligning the water pump sprocket to the hub with a threaded stud.

Reinsert the engine cover bolt to the block to the pump, tightening the bolt to 15 foot pounds (20 Nm). Tighten two of the water pump sprocket bolts to the water pump by hand.

Take out the threaded stud that was used to align the water pump sprocket to the hub and attach the last bolt to the sprocket to the pump, tightening all three to 89 foot pounds (10 Nm).

Remove the water pump sprocket holding tool and attach the timing cover to the water pump sprocket access plate, tightening the bolts to 89 foot pounds (10 Nm).

Reattach the splash shield, the right front wheel and the exhaust manifold if applicable.

Refill the engine's cooling system with coolant and reconnect the negative battery cable. Start the car and check for leaks when the engine reaches normal operating temperature.

2.4L Grand Am Engine

Disconnect the negative battery cable and drain out the coolant from the cooling system when the engine is cool.

Disconnect the electrical connector to the oxygen sensor and remove the exhaust manifold heat shield.

Remove the following bolts and studs: the coolant inlet housing bolt connecting the exhaust manifold, the bolt to the exhaust manifold to the brace, the studs to the manifold to exhaust pipe and the bolt to the coolant inlet housing to water pump.

Disconnect the following parts from each other: the exhaust manifold from the exhaust pipe by pulling the pipe downward, the oil pan from the coolant inlet pipe, the camshaft housing from the brake vacuum pipe, the cylinder head from the exhaust manifold, the heater outlet pipe from the heater hose and the timing chain cover from the tensioner.

Loosen and remove the water pump bolts to the engine and the bolts from the pump to the timing chain. Remove the water pump with the cover assembly and remove the cover from the pump.

Install the new pump with new gaskets. Replace the cover and tighten the bolts by hand. Attach the pump to the engine and tighten these bolts by hand.

Attach the pump to the timing chain housing nuts and the coolant inlet pipe to the cover. Also tighten these by hand.

Torque all bolts to the following specifications after all bolts have been inserted and hand tightened: the chain housing nuts to the pump assembly to 19 foot pounds (26 Nm), the water pump assembly to the cover to 124 foot pounds (14 Nm), and the water pump cover to the coolant inlet pipe assembly to 124 foot pounds (14 Nm).

Reattach the cylinder head and the exhaust manifold, tightening the nuts to 11 foot pounds (15 Nm), the coolant inlet pipe to the oil pan, tightening the nuts to 19 foot pounds (25 Nm), and reattach the timing chain tensioner, tightening the bolts to 89 foot pounds (10 Nm).

Reconnect the camshaft housing and the brake vacuum pipe and reattach the front cover, tightening the bolts to 106 foot pounds (12 Nm).

Reattach the exhaust pipe and the manifold, tightening the bolts to 26 foot pounds (35 Nm), the exhaust manifold to the brace, tightening the bolts to 41 foot pounds (56 Nm) and the nuts to 19 foot pounds (26 Nm), the manifold to the exhaust pipe, tightening the nuts to 26 foot pounds (35 Nm), the heater pipe to the heater hose and reattach the exhaust manifold heat shield, tightening the bolts to 124 inch pounds (14 Nm).

Reconnect the electrical connector to the oxygen sensor and the negative battery cable. Refill the engine's cooling system with coolant and start the car. Check for leaks when the engine reaches normal operating temperature.

3.1L and 3.4L Grand Am Engines

Disconnect the negative battery cable and drain out the coolant from the cooling system when the engine is cool.

Remove the accessory drive belt and the water pump pulley.

Loosen and remove the water pump bolts and remove the pump from the engine.

Install the new water pump, tightening the bolts to 89 inch pounds (10 Nm).

Reattach the water pump pulley, tightening the bolts to 18 foot pounds (25 Nm).

Reinstall the accessory drive belt and reconnect the negative battery cable.

Refill the engine's cooling system with coolant. Start the car and check for leaks when the engine reaches normal operating temperature.

Items you will need

  • Drain Pan

  • Wrench set

  • Coolant

  • Car jack

 How to Replace the Water Pump in a Pontiac Grand Prix

5.3L Grand Prix Engine

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

Remove the battery from the engine along with its tray.

Take the drive belt out of the engine.

Loosen and remove the three bolts to the water pump and remove the pump, throwing away the gasket.

Clean the gasket mating surfaces and install the new water pump with a new gasket, tightening the bolts to 89 inch pounds (10 Nm).

Reinstall the drive belt and the battery with the battery tray.

Refill the engine's cooling system with coolant. Start the car and check for leaks when the engine reaches normal operating temperature.

3.5L Grand Prix Engine

Partially drain the coolant from the cooling system.

Disconnect the surge tank outlet hose and remove the drive belt.

Remove the idler pulley and the water pump pulley, making sure to note the locations of the bolts as you remove them as they are various lengths.

Loosen and remove the bolts to the water pump, also taking note at their locations, and remove the pump.

Install the new water pump with a new gasket, tightening the bolts to 124 inch pounds (14 Nm).

Reattach the water pump pulley, tightening the bolts to 106 inch pounds (12 Nm).

Reinstall the idler pulley, tightening the bolts to 37 foot pounds (50 Nm) and install the surge tank hose and drive belt.

Refill the engine's cooling system with coolant.

Start the car and check for leaks when the engine reaches normal operating temperature.

3.4L and 3.1L Grand Prix Engines

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

Disconnect the negative battery cable.

Remove the accessory drive belt guard and the accessory drive belt.

Loosen and remove the water pump pulley bolts and remove the water pump pulley.

Remove the water pump bolts and remove the water pump.

Install the new water pump along with a new gasket, tightening the bolts to 89 inch pounds (10 Nm).

Reinstall the water pump pulley and tighten the bolts to 18 foot pounds (25 Nm).

Reattach the accessory drive belt with the drive belt guard.

Refill the engine's cooling system with coolant.

Start the car and check for leaks when the engine reaches normal operating temperature.

Items you will need

  • Drain pan

  • Wrench set

  • Coolant

About the Author

This article was written by the It Still Runs team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Runs, contact us.

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