I am currently interested in cooling systems. I have read in a little more intensively into the matter. Cooling liquids are also an almost more complex topic like motor oils. What I have noticed so far is that not all cooling systems are built the same way. The classic arrangement is an engine with cooling channels and 2 possibilities as the cooling water in the circle swells, either directly back or over the cooler. That’s actually the same with everyone. How far the system is under pressure i The pressure only goes up to the cooler cover. This has a special structure and 2 seals. The outer seal should always be tight, the inner one is spring loaded and opens up at nominal pressure and leaves the excess over a hose which goes away between the two seals in the overflow tank. This has even above a overflow with it not bursts. Many cars and above all almost all liquid-cooled motor wheels In the USA, too, this system is the normal case. Only VW, for example, is doing this differently. There is pressure on the overflow tank itself. Is there a reason why you have moved on to it, because in the past, VW has done it more “classic”. Does it have something to do with the novel silicate-free liquids that may have little air contact? Which manufacturers still do it like VW?