Tools You'll Need:
* Repair Manual: Absolutely essential for torque specs and detailed instructions.
* Jack and Jack Stands: Safely lift the Blazer.
* Wheel Chocks: For added safety.
* Sockets and Wrenches: Various sizes, including metric and SAE.
* Ratchet: For efficient work.
* Wrench (or socket) for the fan clutch: May require a special wrench.
* Pliers: For various tasks.
* Screwdrivers: Phillips and flathead.
* New Water Pump: Ensure you get the correct one for your engine.
* New Thermostat (recommended): While you're in there, replacing the thermostat is a good preventative measure.
* New Water Pump Gasket: A new gasket is crucial to prevent leaks.
* New coolant: Use the correct type for your engine (usually a 50/50 mix of coolant and distilled water).
* Drain pan: To catch the old coolant.
* Gloves: To protect your hands.
* Safety Glasses: To protect your eyes.
Procedure (General Outline - Consult your repair manual for specifics):
1. Safety First: Disconnect the negative battery terminal. Allow the engine to cool completely before starting. Use jack stands and wheel chocks to secure the vehicle.
2. Drain the Coolant: Locate the drain plug on the engine block (usually low on the side) and drain the coolant into your drain pan.
3. Remove the Fan and Fan Clutch: This often involves removing the fan shroud first, then detaching the fan clutch from the water pump pulley. This can be tricky and may require a special tool. Refer to your repair manual for the correct procedure.
4. Remove the Serpentine Belt: Use a serpentine belt tool to loosen the tensioner and remove the belt. Diagram the belt routing before removal to ensure correct reinstallation.
5. Remove the Water Pump Pulley: Use the appropriate socket and remove the pulley from the water pump shaft.
6. Remove the Water Pump: This is the most labor-intensive part. You'll likely need to remove various bolts securing the water pump to the engine block. Pay close attention to the location of each bolt before removal. The bolts are often located under the water pump itself, making access challenging.
7. Clean the Mounting Surface: Carefully clean the mounting surface on the engine block to ensure a good seal with the new water pump gasket.
8. Install the New Water Pump: Apply a thin bead of gasket sealant (if recommended by the manufacturer) to the new gasket and carefully install the new water pump, ensuring it seats properly. Tighten the bolts in the sequence specified in your repair manual, using the correct torque specifications.
9. Install the Pulley: Reinstall the water pump pulley.
10. Install the Serpentine Belt: Reinstall the serpentine belt, following the routing diagram you made earlier.
11. Install the Fan and Fan Clutch: Reinstall the fan and fan clutch.
12. Refill with Coolant: Refill the cooling system with the correct mixture of coolant and distilled water. Carefully bleed the air from the system following the instructions in your repair manual (this is crucial to prevent overheating).
13. Start the Engine: Check for leaks around the water pump and other connections. Let the engine run until it reaches operating temperature. Monitor the temperature gauge and check for any leaks.
Important Notes:
* This is a simplified guide. The actual process can vary depending on the specific vehicle. A repair manual is essential.
* Torque Specifications: Using the correct torque is crucial. Over-tightening can crack the engine block, while under-tightening can lead to leaks.
* Coolant Type: Use the correct type of coolant recommended for your vehicle. Mixing different types can cause damage.
* Safety: Work in a well-ventilated area. Coolant is toxic.
If you are not comfortable performing this repair yourself, it's best to take your Blazer to a qualified mechanic. This is not a beginner-level repair.
