First note when and where you smell fuel
For diagnosis it matters whether the smell appeared immediately after refuelling, during a cold start, while driving, after stopping or in an enclosed garage. Note whether it is strongest in the cabin, under the bonnet, at the rear of the car or near the filler cap. A stain under the car, difficult starting, rough running or increased fuel use are also useful clues.
When it may only be spilled fuel
A smell may linger briefly after overfilling the tank or spilling fuel on the bodywork. Check that the cap is properly closed and deal with any spill according to the filling station's instructions. If the smell returns on the next drive, remains in the cabin or is noticeable around the parked car, do not dismiss it as residue from refuelling.
What may cause the smell
Possible causes include a leaking pipe or connection, a damaged seal at the pump or injector, a problem with the filler neck or cap, or the fuel-vapour ventilation system. On a diesel, leaking fuel-system components may produce a diesel smell. The smell alone cannot reliably identify the failed component.
When to stop safely and not keep driving
Stop driving if the smell is strong or rapidly worsening, you see a wet trail or dripping fuel, the engine runs roughly, or smoke or a warning appears. Switch off the engine in a safe place, do not smoke or use flames or electrical equipment near the leak, and call roadside assistance. In an enclosed garage, leave safely and arrange ventilation without creating sparks.
What not to try at home
Never look for a leak with a lighter or another flame, and do not touch an unknown liquid. Do not mask the smell with an air freshener or dismantle fuel lines without the correct equipment and procedure. The fuel system may remain pressurised after shutdown; unqualified work increases the risk of fire and damage.
How MotPro inspects the problem
We first clarify when the smell occurs and safely inspect the engine bay, fuel lines, tank area and accessible connections. Depending on the vehicle and symptoms, we may add diagnostics and checks of the vapour-control system, pressure or tightness. We recommend repair only after the cause is found and agree the scope with you in advance.
Every vehicle and fault is different. This article provides general guidance; an inspection of the specific vehicle determines the correct procedure.