The absolute best rust proofing paint on the market is POR15 If it rusts out the only 2 choices you have are making a new one or trying to find a used one. You may also find something aftermarket but im not sure. They are no longer available from the dealer. Better check the one in the lower hose also.
Platinum 5.9 2.25" engine pipes 3" Magnaflow cat, 3" Hooker Aerochamber, 3" tail pipe, Ported kegger, 52MM Throttle Body, 24lb injectors, K&N drop in filter, Cast JEEP valve covers, MSD coil and wires, All new 6 piece clear light kit, 255/65/16 General Grabber HTS, 242 conversion, XJ u-joint front axle shafts