2005 Timing

My uncle just got a 2005 Galant from a used car dealer with 30k miles on it and was told it needed the timing adjusted. He wants to do it himself but he has no idea what the timing should be. I'm assuming it's the L4 engine instead of the V6 becuase I doubt he'd buy something that requires premium fuel. Isn't this something that a Mistsu dealer would do free of charge (under warranty and all that)? If not, what would he need to know to do it himself? He's very proficient with engines (having worked on them for 40+ years). Thanks!