The brief
Mr Goh's C180 had an on-and-off petrol smell, the kind that comes and goes so you can't be sure if it's your car or someone else's. He brought it in to be sure. A petrol smell from your own car is worth tracking down properly, a fuel leak near a hot engine is not something to leave, and a good workshop narrows it down accurately rather than throwing parts at it. The car's fuel system carries petrol from the tank to the engine through rigid lines and short rubber hoses, sealed with clamps. Those rubber hoses age, the rubber hardens and cracks, and a perished hose weeps a little petrol, which you smell more than see, especially when the system's pressurised or the car's warm. A perished fuel hose doesn't reseal, so it needs replacing.
The diagnosis
A careful check of the fuel system, with the system pressurised, traced the smell to a perished fuel hose, weeping a trace of petrol at a hardened, cracked section. The fuel tank, the lines, the filter and the rest of the system checked out, it was that one hose. That's a hose replacement, fresh fuel-rated hose and new clamps where the old had perished, then the area checked dry and the smell confirmed gone.
The work
The fuel system pressure was relieved, the perished fuel hose removed along with the worn clamps, and a new section of genuine fuel-rated hose fitted with new clamps, the connections checked. The system was repressurised and checked carefully for any weep, and the area around it confirmed dry. A road test, with the car warmed up, confirmed no petrol smell and no leak.
The outcome
No more petrol smell, the fuel hose sealed and dry, and no fuel-leak risk near the engine. The C180 went home with the leak sorted at its source. A perished fuel hose only weeps worse and a fuel leak near a hot engine is a real hazard, so tracking it down and renewing the hose put it right, the kind of job worth doing properly.
