I have received multiple engines lately with the Front Eccentric Thermostat or the Thermal Bypass Pellet lodged in the end of the eshaft. This is caused by not installing the Eccentric Thermostat Spring.



I can only surmise that people are assuming that the integrated spring on the thermostat is the spring that needs to be installed, this is incorrect.

The large spring must be installed with either the OE thermostat or the bypass plug.

 

Thanks for posting, Chris

Are these amateur builds? I know I've seen some pretty crazy issues from supposedly 'pro' builds over the years (to include in Mazda reman motors) so nothing surprises me any more.