Rear main or Sump Leak?

[SimonBrown]

Good Evening,
Could I have opinions as to whether my sump or rear main is leaking please. I powdered the inner face of the flywheel, rear of the sump, reaction plate and bell housing. Then took it on a 15 mile run, including about 7 miles of motorway at constant 60 mph. It should be noted that if I drive it on A roads at varying speed it is completely dry. As you can see all the powder has gone from the flywheel face, although it feels damp but not wet to the touch. There is evidence of significant oil down the back of the sump.
Many thanks
Simon

[mgcjag]

Hi Simon..endoscope into bellhouseing...if it crank seal then oil will be running down from crank flange and probably spun all around behind flywheel...Steve

[Jack the lad]

It's possible to buy an additive made by STP which when added to any oil will cause any oil seals that it encounters to expand slightly and in effect seals any leaks. I thought it sounded a bit far fetched but gave it a try and it worked fine. To date I have sealed a couple of auto boxes, a PAS pump and a few engines with it. Considering the work/cost involved on this car it must be worth a try.