1. Remove the gauge: Shut off the engine, allow the engine to cool, and disconnect the battery. Locate the gauge and disconnect it from the capillary tube.
2. Remove the capillary tube: Trace the capillary tube from the gauge to the engine or sending unit. Disconnect the tube at both ends. Avoid bending or kinking the tube.
3. Measure and cut a new capillary tube: If replacing a section, measure the length of the capillary tube that needs replacing and cut a new section to the same length. Replace the entire tube if it's severely damaged.
4. Connect the new tube to the gauge: Attach one end of the capillary tube to the gauge and secure it with a locknut or ferrule. Be careful not to over-tighten and crack the tube.
5. Connect the other end of the capillary tube to the sending unit: Attach the other end of the capillary tube to the sending unit. Tighten it securely.
6. Refill the gauge: Purchase the proper gauge oil from an automotive store. Tilt the gauge face up and unscrew the fill plug (usually a small screw on the back). Use a small syringe or eye dropper to fill the gauge with oil. Fill until it reaches the top.
7. Reinstall the gauge: Position the gauge into place and secure it with the mounting bracket. Connect any electrical connectors and reconnect the battery.
8. Test the gauge: Start the engine and let it warm up to operating temperature. Check the gauge to make sure it's reading accurately.
