I've searched a good bit and found a little info on the symptom but haven't been able to pin down my exact problem. I have diesel in the trunk. The neck seal is new and the fuel lines are dry. The tank is dry except for the bottom...which is why I suspect it is coming out down there. I have not removed it yet as I'm waiting to get it close to empty but I'd like some educated opinions on what to look for.

Do these tanks rust out? The thing looks new, not even dusty being behind that nice cover and the integrity of the metal sounds consistent when tapped with a rubber hammer in different places. Of course, I can't look it over entirely until it's out of the car.

Thanks
Sam

'83 300Dt
'82 300Dt
'76 300D
'91 190E 2.6
'90 190E 2.6

If there is water in the bottom of the tank and the protective coating breaks down with time you can get corrosion and a pinhole through the bottom of the tank. Not that common but does happen on occasion. I have also seen holes drilled accidentally into tanks but not this brand. Usually the old ford fullsize cars. The back of the tank rested on the rear vertical section of the passenger compartment. People would drill through when patching bodies.