i opened up my thermostat housing over the weekend because my car was reading completely cold after about 20-30 minutes of driving. when i pulled the housing off the thermostat was lodged in the housing. i got another thermostat from napa but when i sat it in place there was a little big of wiggle room. i put it in and started the car and bled the coolant. the temp gauge started reading properly so i took the car for a drive. i got about two miles and noticed the temp gauge had dropped all the way to cold as if the car had been sitting for several hours. i havent checked the napa thermostat i just installed but im sure it has lodged itself in the thermostat housing as well and all coolant is bypassing right to the radiator.

the napa flange diameter says it is 2.205 inches. Is the size for the evo a little bigger?

 

This is the third thread on this subject in two weeks, all the same thermostat and all the same problem.

The OEM thermostat has a rubber gasket around the rim. Measuring from the OD of the gasket, the diameter is about 2 5/8 inches.

 

sorry i did a search on the forums before i posted and did a little google searching with some results on evom.

maybe im just retarded at searching these forums >.<

 

Not my intention to hit you with the search button stuff, I just wanted you to know that this is a pattern. So far as I know, the only thermostat that works right comes from Mitsu. I went the same route with Advance Auto and wasn't able to obtain a correct thermostat.

 

Same thing happen to me with the Advance Auto thermostat. It was completely different from the original.

 

its all good man. thats the second thermostat for me in three days. my mechanic friend ordered the second one form his shop and he specifically wrote down 03 lancer evolution 2.0T. i need to call the local mitsubishi dealership today and get the right one.