I understand that, sorta like having an ac compressor failure, you have to make sure you have to get all debris out. The part I disagree on and that I was trying to say was simply if the old cooler lines were removed, not damaged, and installed correctly that I cannot see where it is a warranty issue. Cooler lines are his. If you work on a vehicle do not cause the damage, installed them correctly and they fail months latter, would you pull out your wallet and hand the customer the money for replacement parts that they never paid for? Would you take responsibility for any of the parts on that vehicle, that were not new 5 months latter? Old stuff can fail. If the guy is giving him a warranty on his work and the new parts what else can you do, maybe they got some signals crossed and the op wanted it done right garage thought he wanted it done as cost effective as possible. Not tryng to arguee but he cant call Napa or whoever and say I got a customer who did not pay for new lines, he needs em I will take one of your free ones since I bought the parts for the repairs the customer and me had agreed upon.