However, if you're determined to do it yourself, here's a general overview. This is NOT a comprehensive guide, and you will need to consult a repair manual specific to your 1991 Buick Century engine (likely a 3.3L V6 or a 3.8L V6). A Haynes or Chilton manual is a good starting point.
Before You Begin:
* Consult a Repair Manual: This is absolutely crucial. The manual will have detailed instructions, torque specifications, and diagrams specific to your vehicle.
* Gather Tools: You'll need a variety of tools, including wrenches (metric), sockets, ratchet, jack stands, jack, timing belt tools (possibly including a crankshaft pulley holder), pry bar, and possibly a torque wrench.
* Safety First: Disconnect the negative battery terminal before you start. Wear safety glasses and gloves. Work in a well-ventilated area.
General Steps (Highly Simplified):
1. Preparation: Disconnect the battery. Drain the coolant (if necessary depending on access). Remove any components that obstruct access to the timing belt, such as belts, pulleys, covers, and possibly the power steering pump. Consult your repair manual for the precise order and procedure.
2. Access the Timing Belt: This involves removing various covers and potentially other parts. Your repair manual will guide you through this process.
3. Align the Camshaft and Crankshaft: This is CRITICAL. The crankshaft and camshafts must be precisely aligned to the timing marks indicated on the pulleys and engine block. Failure to do this will result in valve damage when you start the engine. This usually involves turning the engine by hand and observing the alignment marks.
4. Remove the Old Timing Belt: Carefully remove the old timing belt, noting its routing. Take pictures if you need to.
5. Install the New Timing Belt: Install the new timing belt, ensuring it's properly seated on all pulleys and follows the correct routing (again, refer to your repair manual).
6. Re-installation: Reinstall all components removed in the previous steps, ensuring everything is securely tightened to the manufacturer's torque specifications.
7. Check Timing Alignment: Double-check the timing alignment one last time before starting the engine.
8. Refill Coolant: Refill coolant to the proper level.
9. Start the Engine: Carefully start the engine and listen for any unusual noises. Check for leaks.
Important Considerations:
* Water Pump: Many mechanics recommend replacing the water pump at the same time as the timing belt, as the labor involved is similar. The water pump is often driven by the timing belt.
* Tensioner and Idler Pulleys: Inspect the tensioner and idler pulleys. These often show wear and may need replacement as well.
* Torque Specifications: Use the correct torque specifications for all bolts and nuts; use a torque wrench.
Disclaimer: This is a highly simplified overview. Replacing a timing belt is a complex process. Improperly installing a timing belt can result in catastrophic engine damage. Consult a professional mechanic if you are not comfortable performing this repair yourself. Using an incorrect procedure could severely damage your engine. Always refer to a repair manual specific to your vehicle's year, make, and model.
