However, if you're determined to do it yourself, here's a general outline. This is NOT a comprehensive guide, and you'll need a detailed repair manual specific to your 1991 S10's engine (4.3L V6 or 2.5L/2.8L I4) to provide precise instructions and torque specifications. Failure to follow correct procedures can cause serious damage.
General Steps (vary significantly depending on engine):
1. Safety First: Disconnect the battery negative terminal. Make sure the engine is completely cool.
2. Drain the Engine Oil: This is crucial. Use the correct drain pan and allow ample time for complete drainage.
3. Remove Necessary Components: This will vary drastically depending on your engine. You'll likely need to remove:
* Oil pan: This often requires removing various components to access it, including the skid plate (if applicable), various sensors and sometimes even exhaust components.
* Timing chain cover (if applicable): Some engines require this for oil pump access. This is a complex step requiring precise alignment upon reassembly.
* Other components: Various brackets, wiring harnesses, and other parts might need to be moved or removed to gain access. Consult your repair manual.
4. Access and Remove the Oil Pump: Once the oil pan is removed, the oil pump should be visible. There are typically bolts securing it to the oil pump housing. Take pictures as you disassemble, noting the position of all parts.
5. Install the New Oil Pump: Ensure the new pump is the correct replacement part for your specific engine. Carefully install it, making sure all gaskets and seals are correctly positioned and in good condition. Use new gaskets and seals.
6. Reassemble Everything: Reinstall all components in the reverse order of removal. Pay close attention to torque specifications for all bolts and nuts. Incorrect torque can lead to leaks and damage.
7. Refill with Oil: Once everything is reassembled, refill the engine with the correct type and amount of oil as specified in your owner's manual.
8. Check for Leaks: Carefully inspect all connections and seals for leaks.
9. Start the Engine: Start the engine and check for leaks. Monitor the oil pressure gauge.
Critical Considerations:
* Repair Manual: A factory service manual or a reputable aftermarket repair manual for your specific 1991 S10 engine is absolutely essential. This will provide detailed instructions, torque specifications, diagrams, and component locations.
* Tools: You'll need a variety of tools, including sockets, wrenches, screwdrivers, a torque wrench (essential!), oil pan gasket, oil pump gaskets/seals, and potentially special tools depending on your engine.
* Cleanliness: Keep everything clean. Dirt and debris in the oil system can cause damage.
* Gaskets and Seals: Always use new gaskets and seals when reinstalling the oil pump and oil pan.
Again, this is a complex repair. If you are not comfortable with this level of automotive repair, take your truck to a qualified mechanic. Improperly performing this repair can lead to catastrophic engine failure.
