Not sure what brand you've got, but Autometer specifically states that if the line is kinked it won't register at the gauge:

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Now, we can briefly discuss also how the gauge itself works. What we do is run a hollow copper tube from the end of the line (commonly referred to as the sender "bulb") all the way into the gauge, then cover it with a protective plastic/rubber-like covering. This line is filled with ether gas, so if you have ever broken or cut one and get a funny smell or some white fluid on you, don't worry, it is not harmful. When the sender is in the intake, head, trans or oil pan (or whatever you are monitoring) the temperature heats the ether gas inside the tubing. This makes the gas expand and thus "push" the meter that is inside the gauge. This moves the pointer and shows you the temperature. However, if this hollow copper tube is kinked or doubled-over itself, the line will be shut and the gauge will not work. This moves the pointer and shows you the temperature. However, if this hollow copper tube is kinked or doubled-over itself, the line will be shut and the pressure would not reach the gauge, so you would never see the gauge reflect any temp readings at all. This is also true if the line is ever cut or the sender bulb is removed; once the ether gas escapes the line, there is nothing to "push" against the meter to register any temperature readings at all.