the coolant isn't leaking out yet (that i can tell)! a friend of mine who does fiberglass and resin products said he'll put some carbon fiber over that part of the radiator on sunday. he says carbon fiber resin can withstand higher temps and will bond better to the plastic and the carbon fiber mat would give it much more strength..
"Aussie Desert Cooler's Triple Flow System -
By building internal walls in the radiator, the coolant is
re-routed to pass through the radiator (top to bottom or side to side) three times resulting in three separate exposures to temperature dropping air-flow, with little or no adverse flow restriction.
The result is an average 15 % reduction in radiator outlet temperatures. Aussie Desert Cooler now offers this unique flow design as an option on all non-trans cooler type Brass/Copper or Aluminium radiators in their extensive line of high performance vehicle applications."
These aren't available for a RAV4 but im sure that one could be custom made.....