I can't seem to stop my gas cap from leaking.

Fuel leaks and runs down the side of the quarterpanel when driving around....and with diesel at $5.35/gal in CA...every drop is important.

1st - I replaced the rubber gasket in my existing cap. No joy.

2nd - I had a spare cap from a W124. It has a cork seal, instead of rubber, like the later model cap...but seemed to fit and it's very tight. It also leaks, even though it's tight enough to leave an impression of the filler rim around the gasket.

3rd- Guess I'll have to buy a whole new cap from the dealer.....


But seems like the cap may not be the problem. ???? Perhaps something wrong in the filler neck. Can't see any dings or impressions in the rim of the filler neck.

Any ideas ??....or anyone with similar problem and a fix??

Warren C