Here's a general outline. Consult a repair manual specific to your 1998 GMC Jimmy for detailed instructions and diagrams. Variations may exist depending on trim level and options. Improper procedure can lead to damage or injury.
1. Preparation:
* Safety First: Disconnect the negative battery cable.
* Gather Tools: You'll likely need jack stands, jack, socket wrench set (metric), various size wrenches, screwdrivers (Phillips and flathead), possibly a fuel line disconnect tool, safety glasses, gloves, and rags.
* Empty the Tank: This is crucial! Ideally, run the vehicle until almost empty. You can use a siphon pump to remove any remaining fuel. Never work near an open flame or sparks.
* Locate the Tank: The gas tank is usually located under the vehicle, near the rear axle.
2. Accessing the Tank:
* Raise the Vehicle: Securely lift the Jimmy using a jack and place it on jack stands. Never work under a vehicle supported only by a jack.
* Remove Components: You may need to remove some undercarriage components like the exhaust system (partially or completely), plastic shields or heat shields to gain access to the tank. Your repair manual will specify which components need removal.
3. Disconnecting the Tank:
* Fuel Lines: Carefully disconnect the fuel lines. These will likely have quick-disconnect fittings, but you might need a fuel line disconnect tool to prevent fuel spillage. Use rags to catch any drips.
* Fuel Sender Unit: This is usually wired to the tank. Disconnect the electrical connectors.
* Vent Line: Disconnect the vent line(s) from the tank.
* Fill Tube: Disconnect the fuel filler neck from the tank.
* Tank Straps/Holders: Carefully remove the straps or bolts securing the tank to the vehicle's frame. These are often located on either side of the tank.
4. Lowering the Tank:
* Slowly Lower the Tank: Carefully lower the gas tank. It may be heavy and awkward. Have assistance if needed.
5. Reinstallation:
Reinstallation is the reverse of the removal process. Pay close attention to the proper routing of the fuel lines and electrical connections. Double-check everything before lowering the vehicle.
Important Considerations:
* Fuel Pressure: There might be residual fuel pressure in the lines. Consult your repair manual for proper procedures to relieve this pressure before disconnecting the fuel lines.
* Repair Manual: This is the most crucial element. A repair manual specific to your 1998 GMC Jimmy will provide diagrams and detailed instructions, making the job much safer and easier.
* Professional Help: If you're not comfortable performing this task yourself, take your vehicle to a qualified mechanic.
Remember, working with gasoline is dangerous. If you're unsure about any step, consult a professional. This is a general outline and does not substitute for a proper repair manual. Always prioritize safety.
