Cooling water away…but where?

Moin dear Volvo community For some time now, my elk has been suffering from a loss of cooling water. About 0.2 liters per 150km. Today, I lit up the engine compartment in the hope of finding a leak. Unfortunately, I have to say that I had just turned off the elk and that there were still splashes of water from the road in the engine compartment. Also, a pressure of the hoses did not produce any result. Now, of course, I have the fear of the cylinder head seal is no longer in order. However, I don’t have white steam from the exhaust. At the most when it’s cold. But I think that’s keeping itself within limits. Besides, it runs with LPG, it’s always steaming down anyway. The oil level behaves normal. Do you perhaps have an idea what you could do to exclude, for example, the cylinder head seal? Can you check this without disassembly everything? Can you see what might be done with the candles? Would you be nice if you could give me good advice.