Petrol fumes
Hello all, I have a question that someone might shed some light on before taking the car to the dealer. I just did a 3000 km trip from Switzerland to Croatia and back. Car performed very well and I found ideal cruising speed to sit at 135km @ 3000 rpm. Fuel consumption above that gets ludicrous...anyway on the return leg after the car sat still overnight I picked it up, drove 100 meters from the parking garage to fill it with luggage and noticed a very strong petrol smell at the back of the car and inside as well. No sign of leaks and odd running of the engine. Given I had a look around for leaks I didn't see anything untoward and continued my journey. On the next overnight stop the same thing occurred in the morning. It is only when the car has stood still overnight. When stopped to refill the tank there is no such smell. Very odd..did anyone else have something similar ?
Given as you claim, there are no leaks and assuming that, the only way fuel smell accumulate in the luggage area is the vent valve is leaking fumes into the vehicle and not venting the fumes as it should into the carbon purge valve and consumed into the engine as combustible gases to reduce the effects of the ozone layer. (could be with a dislodge pipe or perished pipe - extremely rare condition)
You may try to leave the fuel filler cap slight off and close the fuel filler flap to allow the fumes to vent into the atmosphere and check the following morning if fumes build up in the vehicle as before.
On a cautionary note please let the vehicle to breathe by opening the tailgate to vacate the build up of fumes and when driving open the rear windows but most of all have no naked flames near the vehicle or light cigar lighters whilst you are with the problem.
The vent valve had been usually mounted on the right hand side (viewing from the rear of vehicle) behind the rear quarter panel. I feel certain the G500 vent valve would be in the same place.
Not the most helpful drawings in the world....
Attached Charcoal Filter EVAP system and Breather ventilation system
You may try to leave the fuel filler cap slight off
This may well solve your problem.
Check hose clips and connections. Likely to be something having come undone.