Procedure to operate an electromechanical level transmitter, wherein a displacer element attached to a measuring wire is lowered into a liquid in a container in such a way that, in a state of equilibrium, a resulting weight force (F res ) of the displacer element is equal to a weight force (F G ) of the displacer element minus a buoyancy force (F B ) of the displacer element that depends on a predefined equilibrium volume (V B ) when immersed into the liquid in the state of equilibrium, wherein the resulting weight force (F res ) is determined and kept constant at a value by means of a corresponding variation in the length of the measuring wire , wherein the value is predefined in such a way that it is equal to a value determined using the predefined equilibrium volume (V B ), said value being the value of the resulting weight force (F res ) in the state of equilibrium in which the predefined equilibrium volume (V B ) is immersed into the liquid , wherein the level (L) of the liquid is determined by means of the length of the lowered measuring wire , characterized in that operation diagnosis is performed, wherein - a density (ρ liq ) of the liquid and the predefined value of the equilibrium volume (V B ) of the displacer element are specified as parameters for the level transmitter, - wherein, on the basis of the parameters, the level transmitter uses an evaluation algorithm to determine the resulting weight force (F res ) of the displacer element in the state of equilibrium, - wherein, for the purpose of operation diagnosis, the predefined value of the equilibrium volume (V B ) of the displacer element is varied with a defined change in the equilibrium volume (ΔV B ) by changing the parameter of the equilibrium volume (V B ) in the evaluation algorithm of the electromechanical level transmitter in such a way that either the equilibrium volume (V B ) is increased up to an upper limit of the equilibrium volume (V BH ), wherein the displacer element is lowered to a first height h B1 measured from the upper edge of the displacer element , or that the equilibrium volume (V B ) is reduced to a lower limit of the equilibrium volume (V BL ), causing the displacer element to be raised up to a second height h B2 measured from the upper edge of the displacer element , and - the resulting change in the length of the measuring wire is determined on the basis of the value depending on the value of the equilibrium volume (V B ) at which the resulting weight force (F res ) is maintained. - a density (ρ liq ) of the liquid and the predefined value of the equilibrium volume (V B ) of the displacer element are specified as parameters for the level transmitter, - wherein, on the basis of the parameters, the level transmitter uses an evaluation algorithm to determine the resulting weight force (F res ) of the displacer element in the state of equilibrium, - wherein, for the purpose of operation diagnosis, the predefined value of the equilibrium volume (V B ) of the displacer element is varied with a defined change in the equilibrium volume (ΔV B ) by changing the parameter of the equilibrium volume (V B ) in the evaluation algorithm of the electromechanical level transmitter in such a way that either the equilibrium volume (V B ) is increased up to an upper limit of the equilibrium volume (V BH ), wherein the displacer element is lowered to a first height h B1 measured from the upper edge of the displacer element , or that the equilibrium volume (V B ) is reduced to a lower limit of the equilibrium volume (V BL ), causing the displacer element to be raised up to a second height h B2 measured from the upper edge of the displacer element , and - the resulting change in the length of the measuring wire is determined on the basis of the value depending on the value of the equilibrium volume (V B ) at which the resulting weight force (F res ) is maintained. <EOS>