I am currently in the process of restoring a MK V. The Smiths water temp gauge provides a read out of 80 Degrees Celsius when the actual water temp is 100 Degrees Celsius and boiling. Can anyone shed light on the function of the 3 screws that can be found on the body of the gauge close to where the capillary tube enters the back of the gauge's body? Are these to simply secure the tube inside the body or do they serve as adjustments to help calibrate a more accurate reading on the gauge?
Any advice would be greatly appreciated.
Regards
Frank