Tools and Materials You'll Likely Need:
* Repair Manual: Crucial for specific torque specifications and detailed instructions.
* Jack and Jack Stands: For safe vehicle elevation.
* Wheel Chocks: For added safety.
* Socket Set and Wrenches: Various sizes, including metric.
* Ratchet and Extensions: For access to hard-to-reach bolts.
* New Water Pump: Ensure it's the correct one for your vehicle's engine.
* New Thermostat (Optional but Recommended): Since you're already in there, it's a good idea to replace it as well.
* New Gasket and Seals: For the water pump.
* Coolant: The correct type for your vehicle.
* Drain Pan: To catch the coolant.
* Pliers and Screwdrivers: Possibly needed for various fasteners.
* Torque Wrench: Essential for tightening bolts to the correct specification.
* Gloves and Safety Glasses: Protect yourself.
General Steps (These are general and may vary slightly):
1. Safety First: Disconnect the negative battery terminal. Place the vehicle on jack stands after securely jacking it up. Use wheel chocks for added safety.
2. Drain Coolant: Locate the radiator drain petcock (usually at the bottom of the radiator) and carefully drain the coolant into a drain pan.
3. Access the Water Pump: This will involve removing various components depending on your engine. Your repair manual will show exactly what needs to be removed (e.g., belts, pulleys, fan shroud, possibly some hoses). Take pictures as you go to aid reassembly.
4. Remove the Water Pump: Once you have access, you'll need to remove the bolts holding the water pump to the engine block. This might require breaking loose stubborn bolts. Be careful not to damage the engine block.
5. Clean the Surface: Carefully clean the mating surface of the engine block where the water pump sits, ensuring it's free from old gasket material.
6. Install the New Water Pump: Apply a thin layer of gasket sealant (if required, check your manual) to the new water pump gasket. Carefully align and install the new water pump, tightening the bolts in a star pattern (or as specified in your manual) to the correct torque specifications.
7. Reassemble: Carefully reassemble all the components you removed earlier, paying close attention to the routing of belts and hoses. Double-check everything before starting the engine.
8. Refill Coolant: Fill the radiator and overflow tank with the correct type and amount of coolant.
9. Bleed the Cooling System: Run the engine for a few minutes, allowing the thermostat to open and the air to bleed out of the system. Check for leaks. Top off the coolant as needed.
10. Test: Drive the vehicle and monitor the temperature gauge. Check for leaks again.
Important Considerations:
* Repair Manual: Cannot stress this enough. A repair manual specific to your 1999 Pontiac Montana is indispensable.
* Torque Specifications: Using the correct torque is critical to prevent damage.
* Coolant Type: Use the correct type of coolant specified for your vehicle. Mixing different types can be harmful.
* Professional Help: If you're not comfortable performing this repair yourself, take it to a qualified mechanic. The cost of a botched repair can far exceed the cost of professional service.
This is a general overview. The specific steps and tools needed will vary significantly depending on your engine. Always consult your repair manual for detailed instructions and safety precautions. Remember safety first!
