Here's a general overview. Specific steps may vary slightly depending on the engine (4.3L V6, 5.7L V8, etc.) you have. Always consult a repair manual specific to your Blazer's year, make, model, and engine for detailed instructions and torque specifications. A Haynes or Chilton manual is a good investment.
Tools You'll Likely Need:
* Repair Manual: Absolutely essential!
* Socket set (metric): Various sizes, including deep sockets.
* Wrenches (metric): Various sizes.
* Ratchet: Both a standard and possibly a breaker bar for stubborn bolts.
* Screwdrivers: Phillips and flathead.
* Pliers: Needle-nose and regular.
* Drain pan: To catch coolant.
* New water pump gasket and seals: Use only OEM or high-quality replacement parts.
* Coolant: The correct type for your Blazer's engine.
* Jack and jack stands: For safe vehicle support.
* Torque wrench: Crucial for proper tightening of bolts to prevent leaks and damage.
* New thermostat (optional but recommended): While you're in there, it's a good idea to replace it.
General Steps (Consult your repair manual for specifics):
1. Safety First: Disconnect the negative battery terminal. Place the Blazer on jack stands securely.
2. Drain the Coolant: Drain the coolant from the radiator and engine block (follow the instructions in your repair manual).
3. Remove Accessory Components: This is where the complexity varies depending on the engine. You may need to remove belts, pulleys, fan, fan shroud, and possibly other components to access the water pump. Take pictures as you go to help with reassembly.
4. Remove the Water Pump: This typically involves removing bolts securing the pump to the engine block. These bolts can be very stubborn due to corrosion. Use penetrating oil if needed.
5. Clean the Surface: Carefully clean the mating surfaces of the engine block and the water pump to ensure a proper seal.
6. Install the New Water Pump: Install the new water pump gasket and carefully install the new water pump, aligning it properly with the engine block. Tighten the bolts according to the torque specifications in your repair manual. Do not overtighten.
7. Reinstall Components: Carefully reinstall all the components you removed earlier, in reverse order.
8. Refill Coolant: Refill the cooling system with the correct type and amount of coolant.
9. Bleed the Air: Bleed the air from the cooling system to prevent overheating (your repair manual will show you how).
10. Check for Leaks: Start the engine and carefully check for any coolant leaks. Let the engine run for a while to reach operating temperature.
11. Recheck Coolant Level: Check the coolant level and top it off if necessary.
Important Considerations:
* Rust and Corrosion: Older vehicles often have corroded bolts. Use penetrating oil liberally and be prepared to work carefully. A breaker bar may be necessary.
* Torque Specifications: Following the torque specifications in your repair manual is critical to prevent damage and leaks.
* Coolant Type: Use the correct type of coolant specified for your Blazer's engine. Mixing different types can be harmful.
This is a simplified overview. Refer to your repair manual for detailed, step-by-step instructions specific to your vehicle. Attempting this without the proper knowledge and tools can lead to damage to your engine or injury to yourself. If you are unsure about any step, consult a professional mechanic.
