Here's a general outline. Specifics may vary slightly depending on the exact engine (4.5L or 4.9L V8). Always consult a repair manual specific to your year and engine for detailed diagrams and torque specifications. A Haynes or Chilton manual is a good investment.
Tools you will likely need:
* Socket set (metric): Various sizes, including a deep socket for the water pump pulley bolt.
* Wrench set (metric): For various bolts and possibly the pulley nut.
* Ratchet and extensions: To reach difficult-to-access fasteners.
* Pliers: Possibly for hose clamps.
* Screwdrivers (Phillips and flathead): May be needed for various components.
* Jack and jack stands: Essential for safe working conditions.
* Wheel chocks: For added safety.
* Serpentine belt tool (optional but helpful): Makes routing the belt easier.
* Torque wrench: Crucial for tightening bolts to the correct specification.
* New serpentine belt: Get the correct size for your engine.
* New water pump pulley: Ensure it's the correct one for your vehicle.
* Shop rags or towels: To keep things clean.
* Gloves: Protect your hands.
* Safety glasses: Protect your eyes.
Procedure (General Steps - Consult your repair manual for detailed instructions and diagrams):
1. Preparation:
* Disconnect the negative battery terminal. This prevents electrical shorts.
* Raise and securely support the front of the vehicle using a jack and jack stands. Engage the parking brake and use wheel chocks.
2. Accessing the Serpentine Belt and Water Pump Pulley:
* Depending on your engine and its accessories, you may need to remove some components for better access. This could include things like the fan shroud, or other ancillary components. Your repair manual will detail this.
3. Removing the Serpentine Belt:
* Loosen the tensioner pulley. This is usually done by using a wrench or socket on a bolt designed for this purpose. The tensioner allows the belt to be loosened and removed. Your repair manual will show you the location and method for loosening your specific tensioner.
* Remove the serpentine belt. Carefully route it off the pulleys.
4. Removing the Water Pump Pulley:
* Locate the water pump pulley bolt. This is usually a large bolt in the center of the pulley.
* Use a socket and ratchet to remove the bolt. You may need a breaker bar or impact wrench if the bolt is seized. Be prepared – it can be very tight!
* Remove the pulley. Once the bolt is removed, the pulley may simply pull off. If it's stubborn, a pulley puller may be necessary.
5. Installing the New Water Pump Pulley:
* Install the new water pump pulley. Make sure it's properly seated.
* Tighten the bolt to the correct torque specification as stated in your repair manual.
6. Installing the New Serpentine Belt:
* Route the new serpentine belt around the pulleys in the correct order. Your repair manual will show you the correct routing. A serpentine belt tool can be very helpful here.
* Tighten the tensioner pulley to restore tension on the belt.
7. Reassembly:
* Reinstall any components you removed for access.
* Lower the vehicle carefully.
* Reconnect the negative battery terminal.
8. Testing:
* Start the engine and check for any belt squealing or other unusual noises. Make sure the belt is properly seated on all pulleys.
* Inspect for leaks around the water pump area.
Again, this is a general overview. Always consult a repair manual specific to your 1990 Cadillac DeVille and its engine for detailed instructions and torque specifications. If you are not comfortable performing this repair, take your vehicle to a qualified mechanic. Incorrect installation can lead to serious engine damage.
