Hello I gave my mini today to a free workshop in Berlin, which makes a good impression. I had changed my chain tensioner myself after he had raced badly at the cold start. After the change it became much better, after an oil change to 0W40 the rattle was gone, except for a little moment at the start. I had brought it to the workshop, so that the initial rattles listen to whether that is so ok. So now I come to the problem. When checking through the engine, it turned out that the 4 cylinder has only 2 bar everyone else have 8! In addition, he seems to have lost about a 1/2 oil in two weeks. What is surprising about this is that I could not notice any loss of performance or other disturbances. The workshop now wants to take the head off, with the corresponding costs. Should you do that right away or are there any other checks you can do before? Until where in the engine actually go the pressure measurements?? Could it be that for example the scrumps is loose? It was recently the exhaust change? Would be grateful for the company?