Why car using 20 litres per 100km? on 1997 Mercedes-Benz C280

60litres covers only 300km.

Asked by for the 1997 Mercedes-Benz C280
have diag done to detemine what is causing the excessive oil usage
1 more answer
fuel leak maybe. is it mis-firing at all? could be ignition prob. especially with a big engine like that.