Thanks Saleem, for the kind advice. I have already reported to service adviser and they didn't find anything wrong. This smell comes only sometimes and not always, so it's difficult to attack and fix. And yes I park in sun and now since few days I leave little windows open to reduce the glasshouse effect heat building inside the car cabin. My doubt is same as your and that's why now on every refueling I get filled only three quarter and not full tank as may be during the heat fuel expands and vapor get leaks from any rubber seal. I only have an option to wait to let this smell increase so that service adviser can experience it and offer a fix for this problem.