AFN ESP Leak: Troubleshooting & Repair Guide

Hello,


I replaced the seal between the fuel filter housing (MSW) and the pump housing on my car, as there was a significant leak coming from the engine side. I bought a Bosch gasket set, followed the instructions carefully, started the engine, and it's leaking almost exactly the same way as before!
Okay, so I removed the MSW (manifold swirl valve), checked the gasket, cleaned everything thoroughly, paid close attention to ensure nothing was misaligned during reassembly, and put it back on. It was sealed then, but now, after 200 km, it's leaking exactly like before.
What did I do wrong? Has anyone else experienced this before? Are there different types of seals/gaskets?


Thank you and best regards.

Toto.