W31x

Hello, I am new at this forum and have following problem with my beloved Chevy Van.

While the engine is running, there is a big fuel loss between the engine block and the gearbox, somewhere above the drive pulley in the area of the flywheel (see attached picture).

I hope you can imagine it with this picture.

Before I unscrew the gearbox, I wanted to know where the diesel could come from. In this area there is neither a fuel line nor openings / seals for possible locations where diesel could escape. I'm sure that the engine block has no cracks. The exhaust smoke is cold, whitish and warm, almost transparent.
I could imagine that a "sealing ring" in the area of the pushrod could be damaged (which could be the only for me possible position), but even in this area I would rather expect an oil loss than a fuel loss.
After turning off the engine, it is still dripping very much in the faulty area. The fuel also retreats from the fuel line in the course of time and then has to be pumped forward (to the engine) again to allow a new start.

Unfortunately, I do not have such a good endoscope, so finding the failure is not easy (biggest fuel loss occurs mostly while engine is running -> and the flywheel rotates very fast).
Maybe someone can give me a hint or a way to solve the problem before I unscrew the gearbox.

Thank you!