Tools You'll Need:
* Wrench: The correct size for your sending unit (usually 7/16" or 1/2"). A socket wrench is recommended for easier access and better control.
* Drain pan: To catch any spilled oil.
* Rags or shop towels: For cleaning up spills.
* New oil pressure sending unit: Make sure you get the correct replacement part for your 1966 Mustang 289.
* Penetrating oil (optional): If the sending unit is stuck.
* Gloves: To keep your hands clean.
Procedure:
1. Warm up the engine: Run the engine for a few minutes to warm the oil, making it slightly less viscous and easier to drain. Don't let it get too hot!
2. Locate the sending unit: The oil pressure sending unit is typically located on the engine block, near the oil filter. It's a small cylindrical unit with a wire connected to it.
3. Prepare for removal: Place your drain pan under the sending unit to catch any oil that might spill.
4. Remove the wire: Disconnect the electrical wire connected to the sending unit. It's usually a single wire; carefully unplug it.
5. Loosen the sending unit: Using the correct wrench, carefully loosen and remove the sending unit. It's threaded, so turn it counterclockwise. If it's stuck, try applying penetrating oil and letting it sit for a few minutes before attempting to loosen it again. Use slow, steady pressure to avoid stripping the threads.
6. Clean the threads: Clean the threads on the engine block thoroughly using a rag or brush. Any debris could interfere with the new sending unit's seal.
7. Install the new sending unit: Carefully screw the new sending unit into the engine block by hand until it's snug. Then, using your wrench, tighten it to the manufacturer's specified torque (check your owner's manual or the new sending unit's instructions; overtightening can damage the threads). Don't overtighten.
8. Reconnect the wire: Reconnect the electrical wire to the new sending unit.
9. Check for leaks: Start the engine and check for any oil leaks around the new sending unit. Let the engine run for a few minutes.
10. Inspect and clean: Check the area around the sending unit for any leaks. Wipe away any spilled oil with rags.
Important Considerations:
* Oil Pressure Gauge: After installation, start the engine and verify that your oil pressure gauge is working correctly. If not, there may be an issue with the gauge itself, the wiring, or the new sending unit.
* Torque Specification: It's crucial to tighten the sending unit to the correct torque. Overtightening can damage the threads, while undertightening can lead to leaks.
* Safety First: Always work in a well-ventilated area and avoid touching hot engine parts.
This guide provides general instructions. Always consult a repair manual specific to your 1966 Mustang 289 for detailed instructions and torque specifications. If you're not comfortable performing this repair yourself, it's best to take your car to a qualified mechanic.
