Tools You'll Likely Need:
* Repair Manual: Absolutely essential! A Haynes or Chilton manual specific to your year and model will be invaluable.
* Socket Set and Wrenches: Various sizes, including metric.
* Ratchet and Extensions: To reach hard-to-access bolts.
* Screwdrivers: Phillips and flathead.
* Pliers: For hoses and clamps.
* Drain Pan: To catch coolant.
* New Water Pump Gasket and possibly Thermostat Gasket: Always replace these when doing a water pump.
* Coolant: The correct type for your engine.
* Jack and Jack Stands: Safely support your vehicle.
* Torque Wrench: Crucial for proper tightening of bolts.
General Steps (Consult your repair manual for specifics):
1. Safety First: Disconnect the negative battery terminal. Let the engine cool completely before starting work. Wear safety glasses.
2. Drain the Coolant: Locate the drain plug on the engine block and radiator. Place the drain pan underneath and carefully drain the coolant.
3. Remove Accessory Components: Depending on the exact configuration, you may need to remove or loosen various components to access the water pump. This might include:
* Serpentine Belt: Remove the belt tensioner to remove the serpentine belt.
* Fan and Fan Shroud: May need to be removed or moved out of the way.
* Pulley(s): The water pump pulley may need to be removed.
* Possibly other components: Check your repair manual.
4. Detach Hoses: Carefully disconnect the upper and lower radiator hoses and any other hoses connected to the water pump. Have rags handy to absorb any spilled coolant.
5. Remove Water Pump Bolts: The water pump is typically held in place by several bolts. Carefully remove these bolts using the appropriate sockets and wrenches. Pay close attention to the bolt locations and order.
6. Remove the Water Pump: Once the bolts are removed, the water pump should come off. It might be slightly stuck due to corrosion; gently pry it loose using a plastic or wooden pry tool to avoid damaging the engine block.
7. Clean the Mounting Surface: Thoroughly clean the mating surfaces on the engine block and the water pump housing of any old gasket material.
8. Install the New Water Pump: Install the new water pump gasket, ensuring it's properly seated. Carefully install the new water pump, aligning it with the mounting holes. Tighten the bolts to the torque specifications in your repair manual. Do not overtighten.
9. Reassemble Everything: Reinstall all the components you removed in reverse order, paying close attention to the hoses and belt routing. Refer to your repair manual.
10. Refill the Coolant System: Fill the radiator and coolant reservoir with the correct type and amount of coolant. Bleed the air out of the system according to your repair manual's instructions. This is crucial to prevent overheating.
11. Check for Leaks: Start the engine and let it run for a while, checking for any leaks around the water pump and hoses.
Again, I strongly emphasize consulting a repair manual specific to your 1994 Pontiac Trans AM 3.4L OHC engine. This guide is a simplified overview and omits many crucial details. Incorrect procedures can lead to significant engine damage. If you're not comfortable with this repair, take it to a qualified mechanic.
