Coolant on strip – No influence!
A square wave electric current is applied to coils which then emit weak magnetic fields to the surroundings. If a metal strip is in the vicinity, the field energy will penetrate and saturate the metal. When the current is shut off the magnetic field is reversed and a response signal is captured by receiver coils. The size and shape of this response signal is entirely dependent on metal in the immediate proximity, all other substances are invisible to the gauge. This is what makes it possible to measure distance, shape and resistivity while being unaffected by the environment.
Coolants have no influence at all on the measurement signal.