The integration of ethanol into gasoline presents compatibility challenges for automotive fuel-system materials. In this study, the degradation of NBR-PVC fuel hoses exposed to ethanol-gasoline blends (E30, E50, E70, and E100) was investigated under dynamic flow conditions. A custom-designed test rig simulates real-time fuel circulation for 1,200 h. FESEM, ATR-FTIR, and elemental mapping analyses revealed ethanol-induced degradation, including dehydrochlorination, plasticizer leaching, and filler detachment. Among the blends, E30 exhibited the least material degradation, whereas E100 showed significant surface damage and chemical alteration. This study recommends multilayered fuel hose structures with ethanol-resistant inner linings for enhanced durability.