are there more than 1 size options for thermostats on the Gen 2 3.0? all the parts houses show the same size options, but when i go to install, even with the rubber gasket installed, the recess on the engine side is maybe 1/4" larger than the thermostat mating surface. this is causing a slight leak. when i took it off i noticed the P.O. added silicone to the piece you bolt on, assumingly to stop the leak i am getting. what gives?

 

No, just one. Toyota #90916-03079. Same one for the entire run of the 2nd gen.