1. Support the Engine: This is CRUCIAL. The oil pan is relatively heavy, and if it catches or hangs, you could potentially damage the engine or yourself. Use jack stands properly placed under the engine to support its weight *before* you attempt to remove the oil pan. Never rely on a jack alone.
2. Access: You'll need adequate clearance underneath the vehicle. Jack it up high enough and use jack stands. Consider removing the skid plate (if equipped) for better access.
3. Disconnect the Oil Pan: After loosening all the bolts, the pan *might* fall away gently. However, this is rarely the case. Gently tap around the pan's perimeter with a rubber mallet. This can help break the seal between the pan and the engine block. Start gently; you don't want to damage the pan.
4. Dealing with Resistance: The oil pan likely has a sealant that's hardened over time. This will make it stick to the engine. If tapping doesn't work:
* Pry Bars: Use *plastic* or *wood* pry bars carefully and strategically around the perimeter. Metal pry bars risk scratching or damaging the engine block. Insert the pry bar between the pan and the block, applying gentle but firm pressure. Work your way around the perimeter, freeing the pan gradually.
* Penetrating Oil: If the pan is particularly stubborn, consider applying a penetrating oil (like PB Blaster) to the seam between the pan and the block. Let it sit for a while (ideally overnight) to help loosen the sealant.
5. Lowering the Pan: Once the pan is mostly free, carefully lower it. Be aware of any wiring or other components that might be in the way.
Important Considerations:
* Fluid Drainage: Ensure the engine oil is completely drained before removing the pan.
* Sealant Replacement: You'll almost certainly need a new oil pan gasket when reinstalling. Use a quality gasket and the correct amount of sealant as specified in the repair manual.
* Repair Manual: Obtain a repair manual specific to your 1998 Cadillac STS. This will provide detailed instructions, torque specifications for bolts, and other crucial information. This is highly recommended to avoid damaging the engine.
* Safety First: Always work in a well-ventilated area. Use safety glasses and gloves.
If you're not comfortable with this procedure, it's strongly recommended you take your car to a qualified mechanic. Improper removal can lead to significant engine damage.
