Oil tub Question what’s up there?

Hello, I’m new here. I inherited the Calibra (2.0l 1992 136tkm) from my father and of course he loses oil slightly. But I want to keep it (drive 518Touring). I am pleasantly surprised by the consumption (7,3l fully loaded at 130km/h)!!! I once got the seal for the round part that is installed in the front of the oil tank, because I thought it would come out there. There’s also a cable on it. Is that the Ól pump? Can I change the seal without taking off the oil tank, so just the three screws. Since I got 2 seals from Opel (outside/inside?) I think that the oil tank has to be removed as the inner part falls inwards, right? I found nothing in the search!