What is this thing near filler cap?

I noticed a rubber stopper with a hole running through the middle of it laying outside the fuel filler area. It seems to fit in a hole that looks like it makes a tunnel somewhere to the tank? When I tried to put it back in it crumbled apart. What is this rubber stopper for?

It could be a drain to the road for water or fuel that collects in that area either by washing, rain or spilling fuel from the nozzle.

Yep, it sounds like the drain to me.

Have a great day,

It might be a rubber bumper for the lid. There should be two of them. They're held in place by a rubber nipple, which sometimes wears out and breaks off, leaving a hole.

I don't think there's any rubber around the drain hole.

[ATLD]

I agree,

There should be no stopper for the overflow drain by the fuel cap. It is there so that fuel or water drains to the ground through the car and not over the car (paint finish). The stopper is either not susposed to be there and therefore a foreign object, or is one of the rubber bumpers from the fuel door. I wouldn't give this a second thought as it indicates no problem I can see.

ATLD

Actually, the stopper is made of a foam-rubber substance, so it is quite mallable and holds water like a sponge. It also fits like a perfectly into the drain tube. The car is an 85 300SD. Does anyone know where I can get a replacement?