回複：如果你朋友會做人，也許人家會免費送你一個蓋，車子會無事，省心省錢

Actually I think the one thing he could have done is to inspect the cap after the 70k repair. He was already told that the cap needs to be replaced. 

It's very likely that the mechanic can't just give him a new cap because the mechanic screwed up.