My a4 2001 mod 1.6 use about 1 liter oil on about 600-800 km. no oil leak.. No black or blue smoke. The car has just gone 107 000 km.. Changed oil and filter. Didn help. Had it twice to a workshop. They couldent find anything.. I think 1 liter on 600 km sounds like alot.. Anyone might know what it is?