Hi, my coach is a 2003 Safari Panther 4213 with a Cat C-12 505 HP and 135 K miles. I am 2nd Owner of 4 years. First Owner had a Private Extended Machinery Failure Ins. He replaced two aluminum radiators before switching to Brass Cored. That seems to have worked for me...no problems, no over heating RPM's wide open in Mountains while towing. I'm using long life coolant. My previous coach had Cat C-7 330HP and only got 1 mpg better fuel burn. Good Luck... some Coaches are rocks, some are diamonds!