I have a 1990 Audi 90, 2wd. It has 124,000 kms, at certain times (hot or cold dosen't seem to matter) a loud clicking noise comes from the valve cover area. I brought it in and the dealer said my breather hose needed replacing. It seemed to fix the problem for a short while but it is back again. Any thoughts? The breather hose was replaced with a custom made metal one, it is fine. James