I have quite a few number of Linea and T-Jets with gas leak as a result of the faulty O-ring. Most of them (infact almost all of them) were manufactured in March 2011. Seems like the batch of O-rings received by FIAT for March turned out to be with lots of faulty O-rings. @Clash81- This O-ring is a trivial issue though the inconvenience it causes is huge. Take your car to the TASS and get a new O-fing and gas filled. I am quite certain that the culprit here is the O ring although final accurate diagnosis can be made only by the guy checking the car physically.