Hi alxy, I'm currently having this problem as well. The engine oil reading will fluctuate from max when your just started the car , and will rest at +1L when it is driven for 1 hour . Brought my car for under carriage check and found out a major leaking from the engine. Affected parts could be oil sump gasket, steering rack leakage and vacuum pump. Other than that like oil filter housing and valve cover is Ok. The work to replace the oil sump gasket is labour intensive. Need to leave the car overnight.