Modified the Honda thermostat housing: epoxied in an adaptor for one return, used an existing inlet for the second, and threading the housing for the third. Seeing the two thermostat assemblies side by side, it’s no wonder that the aftermarket unit can’t work installed in the same position. I learned later that the aftermarket part can be installed in one of two different positions: replacing the entire Honda assembly, or replacing only the thermostat cover on the Honda assembly. I’d incorrectly used it in place of the Honda assembly, hence the problems. Have to get a bit more hose for the AN fitting, but I’m confident that the cooling issues has been solved.
In other news, the rear uprights contain a rubber bushing (a factory Mazda part that I planned to do away with as time permits) which has shifted such that the uprights are wearing against the upper A-arms. That’s no good and has to be fixed, either with more sturdy bushings, or better yet, replacing it with spherical bearings. Parts are on the way.
Header wrap arrived but that’s for later this week. Speaking of the header, a buddy, (thanks, Raul!) pointed out that factory exhaust manifold gaskets won’t seal well when feeding a turbo due to the back-pressure. He recommended a gasket by Remflex, which has a very good reputation for sealing and staying sealed. A gasket is on the way.