Ever since I first bought my 84 500sel, there has been an annoying and very pungent raw fuel odor coming from the trunk. It is worst when I have just filled up the tank, and it wafts in most noticeably through the rear speaker holes in the trunk. It seems to slowly dissipate as my tank level drops, until I refill again at which point it returns with a vengeance. This smell does not make my car very pleasant to ride in, and nothing I have tried so far has worked. I have replaced the fuel cap seal as well as the filler neck seal to no avail. I am unsure of the exact origin of the odor, but I know it is worst when I have just filled up. If I park it right after I fill up for at least a half hour and return, the odor fills the entire passenger cabin and I am bombarded with the smell of gasoline as soon as I open the driver door. My gas tank holds pressure, as the cap is pushed out whenever I unscrew it and is never held in place by a vacuum. So what else is there that could be causing this annoying smell? Please help!