Before You Begin:
* Safety First: Disconnect the negative battery terminal. Wear safety glasses and gloves. Work in a well-ventilated area.
* Gather Tools and Parts: You'll need a complete head gasket set (including head bolts, possibly new head studs if recommended), a torque wrench, various sockets and wrenches, a shop manual specific to your 1996 Eldorado, sealant, a clean workspace, and potentially specialized tools like a head bolt torque sequence tool. The shop manual will be critical for torque specs and procedures.
* Diagnose Properly: Are you *certain* it's a head gasket failure? Other issues can mimic head gasket symptoms (e.g., cracked head, warped head). Incorrect diagnosis leads to wasted time and money.
General Steps (Highly Simplified):
1. Preparation: Drain the engine coolant, disconnect all hoses and electrical connectors related to the engine (including fuel lines – be extremely careful!), remove the serpentine belt, air intake, and other components obstructing access to the cylinder head.
2. Remove the Cylinder Head(s): This involves removing the valve covers, rocker arms, camshafts (potentially), and then carefully removing the head bolts in the correct sequence (crucial to avoid warping the head). The head is heavy; use appropriate lifting equipment.
3. Inspect the Head and Block: Thoroughly inspect the cylinder head and engine block for cracks, warping, or damage. Any damage requires repair or replacement. Clean both surfaces meticulously.
4. Replace the Head Gasket: Apply a thin, even bead of sealant (as specified in your shop manual) where required. Carefully install the new head gasket, ensuring it's properly seated.
5. Reinstall the Cylinder Head: Install the cylinder head, ensuring it's properly aligned. Tighten the head bolts in the correct sequence and to the proper torque specifications (using a torque wrench is absolutely mandatory). Consult your shop manual religiously for this step.
6. Reassembly: Carefully reassemble all components removed in step 1, paying close attention to proper hose routing, connector placement, and torque specifications.
7. Refill and Check: Refill the engine with coolant, oil, and other fluids. Check for leaks and ensure everything is functioning correctly. Inspect for any leaks and address them as needed.
Important Considerations:
* Engine Timing: The timing chain or belt may need to be removed and reinstalled correctly; this requires precision and understanding of engine timing.
* Head Surface Machining: If the cylinder head is warped, it may need to be machined flat before reinstallation.
* Torque Specifications: Improper torque can lead to head gasket failure, cracked heads, or other serious engine damage.
* Shop Manual: A shop manual specific to your 1996 Cadillac Eldorado is essential. It will provide detailed instructions, torque specifications, and diagrams.
Disclaimer: This is a general overview. Replacing a head gasket is a complex procedure. If you lack the experience and tools, take your car to a qualified mechanic. Attempting this repair without the proper knowledge and tools could result in significant engine damage and costly repairs.
