Bicycle Mechanics - Grease oozing from bottom bracket???

Granted, the mode of transport was not ideal, but last week I laid my Schwinn MTB in the back of my pickup to take with me for a recreational ride with a friend. Naturally, I had to lay it over on the left side, which put a sidewise pressure on the left crankarm and pedal. (Spare me any nose in the air hoopla about the department store bike, please. It fits me perfect, so it's my casual recreational ride that I don't feel like I have to chain down every moment).

The buddy and I took in the city bike path and several miles of commuter infested campus traffic for a great ride on sunny fall day. My bike is presently stashed at my office.

After parking it in the corner, I noticed a ring of black grease had oozed out around the BB seal. Then, after getting home I took a good look at my Specialized in the carport. The BB is clean and dry.

So ... what might I consider here as the culprit on the Schwinn? I've never been into the BB for maintenance purposes, so I don't know if there are rubberized seals involved, or just a tight fitting metal washer that serves the capping purpose.

Any insight will be appreciated.

Not sure of the age of your bike, but in an older cup and ball BB, grease should be plentiful; less so in a newer cartridge-style. While it should not be oozing out, and I'm trying to think of conditions where that would happen, I don't think it's necessarily a bad thing. No down side to lots of grease in there.

Loosened bottom bracket?

I would think that whatever was leaking was not actually the grease. More likely there is some water in the frame/BB area that is the culprit. I would suggest taking out the seatpost and tipping the bike upside down, letting it sit and see what comes out the seatpost. Grease that is used in a BB should have a consistency that wouldn't seep.

I like Bidaci's answer. Better than mine, and more probable.

Should you wish to go further in depth, it's pretty easy to get into either type of bottom bracket with a crank puller and some other tools. Read Sheldon Brown if you're interested.

Thanks for the several replies. And yes, it could be a water issue, because several week before I transported it the same way and it got rained on severely. I'll check out those angles on the matter.

I abuse it some so this is kind of my "tear up things and learn to fix it" bike. Even so, I've grown attached to the old thing...