I or my workshop wanted to replace the injection nozzles at my TDI. These are attached with a holder to the engine block. The holder is screwed again with an M6 extension screw on the engine block. The block is made of aluminium. The workshop had broken the loosening of the screws first, because the engine was still hot and they did not want to take any risk. We moved the whole thing by two weeks. I should now spray the screws more often with rust solution and that is what they want the whole The Scheffe has addressed me to the risks and side effects. If a screw pulls off, the head must be drilled down and a new thread drilled.. This residual risk is probably present. Now I get easy snap breathing. What can you do in advance to move these crappy screws to loosen.