Its not uncommon for these lines to get bent or damaged during service. Always inspect the integrity of your hard lines during reassembly. This line has a threaded provision for the fuel temperature sensor GM # 97224993.
This is a genuine OE replacement return hard line. #11 in illustration above.
2001-2004 LB7 Duramax 6.6L
Note: We can confirm fitment with your vin if you wish.