After weeks, months, it really feels like years, I finally got the 1998 Subaru Forester back together (head gaskets, timing belt, valve adjustment, clutch and as many new parts as I could reach) and actually running (Two weeks of cylinder 2, 4 misfire and I gave up and took it in to the dealer for diagnosis - I screwed up the valve adjustment too tight).
So now I'm actually driving it around (my DD 1991 Caravan went to the great scrapyard in the sky - head gasket failure and terminal body rust) and noticed an oil puddle. I think I screwed this up too - Rockauto listed an oil pan gasket so I installed that as long as the engine was out. Turns out 98 Foresters use RTV only. The gasket made the bolts a tad short. I assumed that the bolts needed tightening. After unbolting the engine mounts, I lifted the engine up enough to just barely with a lot of cursing blindly able to tighten the rear row of bolts. Still leaking. I tightened everything up all around - still leaking.
I took a real close look at the leak. It looks like the pan had rusted through?! So - is it possible to weld up that leak with the oil pan still on the car? MIG and oxy/acetyl is available. Probably stupid question - do I have to drain the oil first?
I wouldn't expect a fire I don't think. Those look like pinholes. I'm assuming JB Weld isn't going to stick with oil dripping out of it. MIG would be fast. The oil would be a large heat sink and there's not much O2 in the pan which is why I don't think there would be a fire.
The correct way is to drain, drop the pan - pain in the ass. More correct is probably to buy a new oil pan.