A quick google would find many hobbyists claiming that adding a restrictor in the coolant path can solve an overheating problem. That has been claimed vehemently here too many times. Google further and you might find the writeup by a Robertshaw engineer who apparently found the source of this false idea. It was a solution for early flat-head V-8's which would burp coolant out the radiator due to excessive water pump pressure, which was problematic, but a different problem. The easiest counter to this absurd claim is to ask the genius if perhaps the T-stat should then be designed to close more as coolant temperature rises.
