However, if you're determined to do it yourself, here's a general overview. Remember, this is a *simplified* explanation and you'll need a detailed repair manual specific to your Blazer's engine (4.3L V6 or 4.6L V8 are the most common) for accurate steps, torque specifications, and diagrams.
Before You Begin:
* Consult a repair manual: This is absolutely crucial. A Haynes or Chilton manual for your specific year and engine will provide detailed instructions, diagrams, and torque specifications.
* Gather tools: You'll need a comprehensive set of tools including wrenches (metric), sockets, ratchets, jack stands, a timing belt wrench, pulley pullers, possibly a crankshaft holding tool, and a new timing belt kit (belt, tensioner, idler pulleys, water pump - often recommended to replace at the same time).
* Safety first: Disconnect the negative battery terminal. Work in a well-ventilated area. Use jack stands properly and ensure the vehicle is securely supported. Wear safety glasses.
General Steps (Highly Simplified):
1. Prepare the vehicle: Disconnect the battery, drain coolant (if replacing the water pump), and remove the serpentine belt. You may need to remove other components for access (depending on your engine, this could include various covers, pulleys, etc.). The repair manual will detail these steps precisely.
2. Locate Timing Marks: Carefully find the timing marks on the crankshaft, camshaft(s), and possibly other components. These marks must align perfectly to ensure proper engine timing. The repair manual shows you exactly where to find these marks.
3. Remove the Old Timing Belt: This usually involves loosening or removing the tensioner to release the belt's tension. Again, your repair manual will give precise instructions on this.
4. Inspect Components: Carefully inspect the old timing belt, tensioner, idler pulleys, and water pump for wear and tear. Replace anything that shows significant wear.
5. Install the New Timing Belt: Install the new timing belt, ensuring it's properly seated on all pulleys. Use the repair manual to correctly route the belt.
6. Tension the Belt: Use the timing belt tensioner tool to properly tension the new belt according to the specifications in your repair manual. This is critical for proper engine operation.
7. Reassemble: Reinstall all removed components in the reverse order of removal. Be sure to torque everything to the correct specifications as indicated in the manual.
8. Refill Coolant: If you replaced the water pump, refill the cooling system with the proper coolant and bleed the system of any air pockets.
9. Recheck Timing: After reassembly, double-check the timing marks to ensure they are still aligned.
10. Start the Engine: Carefully start the engine and listen for any unusual noises. Check for leaks and ensure the engine runs smoothly.
Disclaimer: This is a highly simplified overview. Attempting this repair without the proper knowledge, tools, and a detailed repair manual is strongly discouraged. Incorrect installation can severely damage your engine. Consult a professional mechanic if you're not experienced in this type of repair.
