This is NOT a DIY job for someone without experience working on fuel systems. Improperly handling fuel lines can result in injury from fire or fuel inhalation. Furthermore, you'll need special tools and safety precautions.
Here's what's involved (generally):
* Safety First: Disconnect the negative battery terminal. Allow the fuel system to depressurize. Work in a well-ventilated area, away from open flames.
* Access the Fuel Tank: This typically involves lowering the fuel tank. This requires disconnecting fuel lines, electrical connections, and possibly the exhaust system (depending on the specifics of your Deville). You will need jack stands, safety ramps, and potentially various tools to support and lower the tank safely. Consult a repair manual.
* Remove the Fuel Pump Assembly: The fuel pump module usually houses the fuel filter. You'll need to remove the pump assembly to get to the filter. Be aware there might be fuel remaining in the lines and tank.
* Replace the Fuel Filter: Carefully remove the old filter and install the new one, ensuring proper orientation.
* Reassembly: Reassemble everything in reverse order, making sure all connections are secure.
* Bleed the Fuel System: After reassembly, you may need to prime the fuel system to remove air from the lines. This might involve cycling the ignition key or using a fuel pump assist tool.
Strongly Recommended: Consult a repair manual specific to your 2004 Cadillac Deville. This manual will provide detailed diagrams, torque specifications, and step-by-step instructions for safely dropping the fuel tank and replacing the fuel filter. You can find these manuals online or at auto parts stores.
Consider professional help: Unless you have significant automotive experience, it's strongly advisable to take your Cadillac to a qualified mechanic for this repair. The risk of injury and potential damage to your vehicle far outweighs the cost of professional labor.
