Tools You'll Need:
* Wrench: The size will depend on your sending unit; it's usually a 9/16" or 7/16" wrench. A socket wrench with the appropriate size socket is generally easier to use.
* Socket wrench set: Helpful for other potential fasteners.
* Drain pan: To catch any spilled oil.
* Rags or shop towels: To clean up any spills.
* New oil pressure sending unit: Make sure you get the correct part for your specific Blazer model. The part number is usually found on the old unit.
* Penetrating oil (optional): Can help loosen a stubborn sending unit.
* Torque wrench (recommended): To tighten the new sending unit to the correct specification. Consult your repair manual for the proper torque.
Procedure:
1. Locate the Oil Pressure Sending Unit: It's usually located on the driver's side of the engine block, near the oil filter. It's a small cylindrical unit with a single wire connected to it.
2. Prepare the Area: Position your drain pan under the sending unit to catch any spilled oil.
3. Disconnect the Wire: Carefully disconnect the electrical connector from the sending unit. Take a picture or make a note of how it's connected if you're unsure.
4. Loosen the Sending Unit: Using the appropriate wrench, carefully loosen and remove the sending unit. It may be tight; if so, use penetrating oil and let it sit for a few minutes to help break the connection. Turn it counter-clockwise to remove it.
5. Clean the Area: Use rags to clean the mounting surface on the engine block, removing any old gasket material or debris.
6. Install the New Sending Unit: Carefully screw the new sending unit into the engine block. Tighten it by hand initially to avoid cross-threading. Then use your wrench to tighten it to the manufacturer's specified torque. Over-tightening can damage the sending unit or the engine block.
7. Reconnect the Wire: Reconnect the electrical connector to the new sending unit, ensuring a secure connection.
8. 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. If you see a leak, turn off the engine and re-tighten the sending unit (slightly).
9. Check the Oil Pressure Gauge: After the engine has been running for a few minutes, verify that the oil pressure gauge is reading correctly. If the gauge is not working, there could be an issue with the gauge itself or the wiring.
Important Considerations:
* Consult a Repair Manual: A repair manual specific to your 1997 Chevrolet Blazer will provide detailed diagrams and torque specifications. This is highly recommended.
* Safety First: Always work in a well-ventilated area. Wear safety glasses and gloves.
* Oil Changes: Consider changing your oil after this repair, as you may have introduced some contaminants.
If you're uncomfortable performing this repair yourself, take your Blazer to a qualified mechanic. It's a relatively simple repair, but improper installation can lead to oil leaks or engine damage.
