Question: We are having trouble diagnosing the source of a fuel odour in the passenger compartment of a 2011 2,0 BMW X3. We can smell the fuel odour in the passenger compartment and have visually checked all of the fuel pipe connections which are tight and not leaking fuel. Can you help?
Answer: Yes, this fuel odour issue affects X3 (F25) and X4 (F26) models with petrol engines and it is due to unsatisfactory design of the underbody shield causing excessive heat build up in the evaporative emission (EVAP) canister. Remove the underbody shield. Use 7 mm drill to make two holes in the underbody shield fig1.1. Modify the underbody shield by cutting out sections as indicated fig1.2. Fit heat shield to the underbody shield fig1.3. Refit the underbody shield. This procedure should eliminate the fuel odour in the passenger compartment.