Is it possible for a fuel system to develop a leak that has no visible evidence such as stain or spot, and if so, how?
It is indeed possible for a fuel system to develop a leak with no visible evidence. This could happen if fuel is leaking from a small crack or hole and evaporating quickly due to the system's pressure, or if the fuel is seeping out so slowly from a faulty seal or joint that it evaporates before it can form a spot.
Explanation:
Yes, it's certainly possible for a fuel system to develop a leak that does not leave visible evidence such as stain or spot. The majority of fuel systems are pressurized, which means even a small leak can evaporate very quickly, leaving no evidence of its existence. One way this could occur is if there's a crack or hole in the fuel line or tank in a place that is not readily noticeable. Curved areas or where the material is thin could be susceptible. When the fuel system is pressurized during operation, the liquid would turn into a gas as it leaks, evaporating into the air before it has a chance to pool. A more insidious kind of leak could result from faulty sealant or joints. Small quantities of fuel might seep out, but the rate is so slow that the fuel evaporates before it can form visible spots.