I have a gas odor in the passenger compartment and trunk area of my 89 560SL. It is very noticeable after the car has been sitting for over a few hours and goes away while driving. I have not seen any fuel stains in the car or on my garage floor. I also notice that there is a release of pressure when I undo my gas cap to refuel. Is this gas odor a common problem??

Somewhat common, but repairable. There is an expansion tank just above the fuel tank that allows vapors to be returned to engine, purge system. Common for these to breath!! Also & first make sure that the filler neck seal is in good shape.

560SL Gas Odor
 

M.B.DOC, Thanks for the speedy reply. Do you have any idea what kind of cost I would be looking at to replace the expansion tank?